F1 PNW Insect Management Handbook Horticultural, Landscape, and Ornamental Crops Christmas Tree Plantation Pests Chal Landgren and Franki Porter Latest revision—March 2017 In all cases, follow the instructions on the pesticide label. The PNW Insect Management Handbook has no legal status, whereas the pesticide label is a legal document. Read the product label before making any pesticide applications. Notes 1. Product names are listed as examples only. There may be numerous product options for some active ingredients. 2. Experience has shown that use of pyrethroid insecticides is associated with subsequent spider mite outbreaks. Therefore, monitor fields closely after using these materials. 3. Check current label for application options (i.e. aerial vs. ground only), restrictions, re-entry intervals, pollinator safety, groundwater and stream buffer requirements, application timing, etc. 4. To avoid resistance, growers are advised to not use repeated application of the same active ingredient or repeated use of chemicals in the same mode of action group. Note: Products are listed in alphabetical order and not in order of preference or superiority of pest control. Pests common to Douglas-fir, True Fir, Pine and Spruce Christmas tree (Common pests)—Conifer aphid Cinara occidentalis and Cinara abietis Pest description and crop damage C. abietis are large, dark aphids typically feeding on upper stems and tended by ants. May distort stems. C. occidentalis feed at the base of needles on 1 year and older foliage, often in the lower portion of the tree and may be quite damaging. See table: Hosts and Symptoms of Major Aphid and Adelgid Pests of Christmas Trees Management—cultural control C. abietis is easily spotted and often controlled by squishing colonies by hand or spot spraying. Minor outbreaks of both species may be kept in check with beneficial insect predators or spot treatments. Management—chemical control ♦ azadirachtin (AzaDirect and others)—Some formulations are OMRI-listed for organic use. ♦ Beauveria bassiana (Naturalis L) ♦ bifenthrin (OnyxPro, Sniper and others)—Restricted use pesticide. (Group 3) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ Chromobacterium subtsugae (Grandevo)—OMRI-listed for organic use. ♦ cyantraniliprole (Mainspring GNL) (Group28) (note: use 2016 or later product label) ♦ dinotefuran (Safari 20 SG)—Check registration status at time of application. (Group 4) ♦ imidacloprid (Admire Pro, Prey 1.6 and others) (Group 4) ♦ insecticidal soaps and oils (Ecotec, M-pede, 440 Superior Oil, Ultra-Pure Oil and others)—Some formulations are OMRI-listed for organic use. ♦ malathion (organophosphate) (various formulations) (Group 1) ♦ pymetrozine (Endeavor) (Group 9) ♦ spirotetramet (Ultor, Movento) (Group 23) ♦ sucrose octanoate (SucraShield and others)—Some formulations are OMRI-listed for organic use. ♦ thiamethoxam (Flagship 25 WG) (Group 4) Management—biological control ♦ aphid predators (Aphidoletes aphidimyza, Aphidius spp., Hippodamia spp., Chrysopa spp.)—Consider attracting predators with forage plantings and using products with low toxicity to predators. See: Biological Control of Nursery Pests Christmas tree (Common pests)—Eriophyid needle mite Epitrimeris spp. and others Pest description and crop damage Very tiny, white, worm-shape mites found along stem and needle bases. Infested foliage takes on an olive-green color; older needles drop prematurely. Management—chemical control Biology and distribution of this mite is not well understood. Apply when new growth is 1 inch or less. ♦ abamectin (Avid and others) (Group 6) ♦ Beauveria bassiana ((Naturalis L)—OMRI-listed for organic production. ♦ carbaryl (Sevin and others) (Group 1) ♦ fenazaquin (Magister) (Group 21) ♦ fenpyroximate (Akari 5SC) (Group 21) ♦ horticultural oil (Omni Supreme, 440 Superior Oil, Ultra-Pure Oil and others)—Test for phytotoxicity for any new product prior to widespread use. Some formulations are OMRI-listed for organic production. ♦ spirodiclofen (Envidor) (Group 23) F2 PNW Insect Management Handbook Christmas tree (Common pests)—Root weevil (adult) Strawberry root weevil (Otiorhynchus ovatus) and others Pest description and crop damage Larvae are cream-colored, C-shaped grubs that feed on roots, sometimes girdling them. Adults feed on Douglas-fir and true fir needles, resulting in characteristic notching. Management—cultural control Site preparation with fallow period prior to planting will reduce habitat for weevils. Management—chemical control Control typically targets adult feeding at emergence. ♦ acephate (Orthene and others) (Group 1) ♦ Beauveria bassiana ((Naturalis L)—OMRI-listed for organic production. ♦ bifenthrin (Brigade 2EC, Bisect, OnyxPro, Sniper and others)— Restricted use pesticide. (Group 3) ♦ dinotefuran (Safari 20 SG)—Check registration status at time of application. (Group 4) ♦ esenvalerate (Asana XL and others)—Restricted use. (Group 3) ♦ permethrin (Ambush and others)—Restricted use pesticide. (Grp 3) ♦ thiamethoxam (Flagship 25 WG) (Group 4) Christmas tree (Common pests)—Spider mite Oligonychus ununguis and others Pest description and crop damage Dark green mite stipples and bronzes needles, beginning at the base. Overwinters as red-orange eggs. Management—chemical control ♦ abamectin (Avid and others) (Group 6) ♦ azadirachtin (AzaDirect and others)—Some formulations are OMRI-listed for organic production. ♦ Beauveria bassiana (Naturalis L)—OMRI-listed for organic production. ♦ bifenazate (Acramite 4SC, Floramite SC) ♦ bifenthrin (Brigade 2EC, OnyxPro, Sniper and others)— Restricted use pesticide. (Group 3) ♦ Chromobacterium subtsugae (Grandevo PTO)—OMRI-listed for organic use. ♦ clofentezine (Apollo SC) (Group 10) ♦ etoxazole (TetraSan 5 WDG) (Group10) ♦ fenazaquin (Magistar) (Group 21) ♦ fenbutatin-oxide (Vendex and others)—Restricted use pesticide. (12) ♦ fenpyroximate (Akari 5 SC) (Group 21) ♦ hexythiazox (Onager, Hexygon, Savey) (Group 10) ♦ insecticidal soaps and oils (Ecotec, Captiva, M-pede, Ultra-Pure Oil, 440 Superior [Winter only] and others)—Some formulations are OMRI-listed for organic production. ♦ malathion (organophosphate) (various formulations) (Group 1) ♦ propargite (Omite-30WS, Omite 6E)—Restricted use pesticide. (Group 12) ♦ spinosad (Conserve and others) (Group 5) ♦ spirodiclofen (Envidor) (Group 23) Management—biological control ♦ Predatory mites (Neoseiulus spp., Phytoseilulus spp. and others)— Note: Little is known regarding controlled releases yet control in plantations from native populations is common. See: Biological Control of Nursery Pests Christmas tree (Common pests)—Spruce budworm Choristoneura fumiferana Pest description and crop damage Green-brown larvae up to 1 inch long feed on foliage and buds of fir, spruce, and Douglas-fir. Management—chemical control Apply May–June or when bud flush is at 90 to 95% and new growth is 0.75 to 1 inch. Pay particular attention to areas adjacent to infested forest. Two applications may be necessary. ♦ carbaryl (Sevin and others) (Group 1) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ Chromobacterium subtugae strain PRAA4-I (MBI-203)—OMRI- listed for organic production. ♦ esfenvalerate (Asana XL and others)—Restricted use pesticide. (Group 3) ♦ emamectin benzoate (Enfold)—Restricted use pesticide. (Group 6) ♦ flubendiamide (Belt SC) (Group 28) ♦ methoxyfenozide (Intrepid 2F) ♦ spinosad (Conserve, Success, Entrust)—Some formulations are OMRI-listed for organic production. (Group 5) ♦ tebufenozide (Confirm) (Group 18) Christmas tree (Common pests)—White grub Includes Polyphylla decemlineata, Plecoma spp., Aphodius spp. Pest description and crop damage Small to large C-shaped, white scarab beetle larva with six legs and a brown head. Grubs feed on roots, often killing young trees. Many follow the soil moisture and may appear absent in summer. Management—biological control Some growers have observed partial control from parasitic nematodes, but results are poorly replicated. Management—chemical control To date, chemical control on established large grub populations has not been effective. ♦ bifenthrin (Bisect, OnyxPro and others)—Restricted use. (Gp 3) ♦ carbaryl (Sevin and others) (Group 1) ♦ imidacloprid (Admire Pro, Nuprid 2F) (Group 4) ♦ thiamethoxam (Flagship 25 WG) (Group 4) F3 PNW Insect Management Handbook Douglas-fir Christmas tree (Douglas-fir)—Black pineleaf scale Nuculaspis californica Pest description and crop damage Gray-black scale. Hosts: Douglas-fir and pine. Management—chemical control ♦ azadirachtin (AzaDirect and others)—Some formulations are OMRI-listed for organic production. ♦ bifenthrin (Bisect, OnyxPro and others)—Restricted use. (Grp 3) ♦ buprofezin (Talus) (Group 16) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ dinotefuran (Safari 20 SG)—Check registration status at time of application. (Group 4) ♦ horticultural oil (Ultra-Pure, 440 Superior Oil and others)—Some formulations are OMRI-listed for organic production. Christmas tree (Douglas-fir)—Coneworm Dioryctria spp. Pest description and crop damage Small creamy-brown moth larvae bore into stems, especially around wounds. Management—chemical control Applications must be made before eggs hatch and larvae tunnel into stem. Using pyrethroid insecticides is associated with subsequent spider mite outbreaks. ♦ carbaryl (Sevin and others) (Group 1) ♦ esfenvalerate (Asana XL and others)—Restricted use pesticide. (Group 3) ♦ phosmet (Imidan 70W) (Group 1) ♦ spinosad (Conserve, Entrust, Success and others)—Some formulations are OMRI-listed for organic production. (Group 5) Christmas tree (Douglas-fir)—Cooley spruce gall adelgid Adelges cooleyi Pest description and crop damage Adelgids appear as small cottony tufts on underside of needles. May cause yellowing, distortion, and premature needle drop. Aphids may distort stems. See table: Hosts and Symptoms of Major Aphid and Adelgid Pests of Christmas Trees Management—chemical control Apply to control crawler stage, usually when new growth is expanding in spring. ♦ bifenthrin (Bisect, OnyxPro and others)—Restricted use pesticide. (Group 3) ♦ carbaryl (Sevin and others) (Group 1) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ dinotefuran (Safari 20 SG)—Check registration status at time of application. (Group 4) ♦ imidacloprid (Admire Pro, Prey 1.6 and others) (Group 4) ♦ insecticidal soap (M-Pede and others)—Some formulations are OMRI-listed for organic production. ♦ spirotetramet (Ultor, Movento) (Group 23) ♦ sucrose octanoate (SucraShield and others)—Some formulations are OMRI-listed for organic production. ♦ thiamethoxam (Flagship 25 WG) (Group 4) Christmas tree (Douglas-fir)—Douglas-fir needle midge Contarinia spp. Pest description and crop damage Adult is a small midge (fly). Larvae mine needles; they often appear as a purple node above which the needles are distorted. Degree day models and traps are available to monitor pest emergence. Management—chemical control Time applications based on adult needle midge trap catch. Time to coincide with adult emergence. ♦ acephate (Orthene) (Group 1) ♦ bifenthrin (Bisect, OnyxPro and others)—Restricted use.. (Grp 3) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ thiamethoxam (Flagship 25 WG) (Group 4) Christmas tree (Douglas-fir)—Douglas-fir twig weevil Cylindrocopturus furnissi Pest description and crop damage Small gray-black weevil with white mottling, sometimes with pink or orange spots. It may kill small branches and sometimes small trees. Management—cultural control Keep trees healthy. Remove and burn infested twigs. Avoid planting on drought-prone or wet sites. Frequently, cultural control provides the only practical option available. Management—chemical control ♦ bifenthrin (Bisect, OnyxPro and others)—Restricted use pesticide. (Group 3) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)—Apply July to early August to seedlings in WA and OR. (Group 1) Christmas tree (Douglas-fir)—Pine needle scale Chionaspis pinifoliae Pest description and crop damage White scale flock needles. Hosts: Douglas-fir and pines. Eggs hatch May or June, perhaps July. Management—chemical control Apply to crawler stage. ♦ azadirachtin (AzaDirect and others)—Some formulations are OMRI-listed for organic production. ♦ bifenthrin (Bisect, OnyxPro and others)—Restricted use pesticide. (Group 3) ♦ buprofezin (Talus) (Group 16) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ dinotefuran (Safari 20 SG)—Check registration status at time of application. (Group 4) ♦ horticultural oil/soap (M-Pede, Ultra-Pure, 440 Superior Oil and others)—Some formulations are OMRI-listed for organic production. ♦ sucrose octanoate (SucraShield and others) F4 PNW Insect Management Handbook Christmas tree (Douglas-fir)—Tussock moth Includes Douglas-fir tussock moth (Orgyia pseudotsugata) Rusty tussock moth (Orgyia antiqua nova) Pest description and crop damage Caterpillars with tufts (tussocks) of hair. Larvae may be found in large numbers under webbing on branches. Management—chemical control Apply to control young larvae when present and feeding. ♦ Chromobacterium subtsugae (Grandevo PTO)—OMRI-listed for organic use. ♦ diflubenzuron (Dimilin 4L, 25W)—Restricted use pesticide. (Group 15) ♦ flubendiamide (Belt SC) (Group 28) ♦ spinosad (Conserve, Success, Entrust)—Some formulations are OMRI-listed for organic production. (Group 5) ♦ tebufenozide (Confirm) (Group 18) Christmas tree (Douglas-fir)—White pine weevil Pissodes strobi Pest description and crop damage A small brown weevil, roughly 0.25 inch long, with the “snout” typical of other weevils. Wing covers are marked with irregular patches of brown and white scales. Important pest of spruce and pine, occasionally a pest of Douglas-fir. Management—chemical control Apply to the tops to control egg-laying weevils as weather warms in spring. Several applications 3 to 4 weeks apart may be necessary. ♦ bifenthrin ( OnyxPro and others)—Restricted use pesticide. (Group 3) ♦ diflubenzuron (Dimilin 4L, 25W)—Restricted use pesticide. (Group 15) ♦ phosmet (Imidan 70W) (Group 1) Pine Christmas tree (Pine)—Black pineleaf scale Nuculaspis californica Pest description and crop damage Gray-black scale. Management—chemical control ♦ azadirachtin (AzaDirect and others)—Some formulations are OMRI-listed for organic production. ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ dinotefuran (Safari 20 SG)—Check registration status at time of application. (Group 4) ♦ horticultural oil/soap (M-Pede and others)—Some formulations are OMRI-listed for organic production. Christmas tree (Pine)—Coneworm See: Christmas tree (Douglas-fir)—Coneworm Christmas tree (Pine)—European pine shoot moth Rhyacionia buoliana Pest description and crop damage Larvae stunt and deform stems, especially terminals. The moth is established in western Washington but still relatively rare in Oregon. Sampling and Thresholds Pheromone traps and degree-day models are available to monitor for adults. Management—chemical control Time applications to coincide with adult emergence. ♦ carbaryl (Sevin and others) (Group 1) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ diflubenzuron (Dimilin 25W)—Restricted use pesticide. (Gp 15) ♦ flubendiamide (Belt SC) (Group 28) ♦ phosmet (Imidan 70W) (Group 1) ♦ spinosad (Conserve, Success, Entrust)—Some formulations are OMRI-listed for organic production. (Group 5) ♦ tebufenozide (Confirm) (Group 18) Christmas tree (Pine)—Pine bark adelgid Pinus strobi Pest description and crop damage Appear as white, woolly mass on trunk or stem. May severely distort new growth. See table: Hosts and Symptoms of Major Aphid and Adelgid Pests of Christmas Trees Management—chemical control ♦ bifenthrin (OnyxPro and others)—Restricted use pesticide. (Grp 3) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)—Apply to control crawler stage around bud break. (Group 1) ♦ dinotefuran (Safari 20 SG)—Check registration status at time of application. (Group 4) ♦ imidacloprid (Admire Pro, Prey 1.6 and others)—Apply to control crawler stage around bud break. (Group 4) ♦ sucrose octanoate (SucraShield and others)—Some formulations are OMRI-listed for organic production. ♦ thiamethoxam (Flagship 25 WG) (Group 4) F5 PNW Insect Management Handbook Christmas tree (Pine)—Pine needle scale Chionaspis pinifoliae Pest description and crop damage White scale flock needles. Hosts: Douglas-fir and pines. Eggs hatch May or June, perhaps July. Management—chemical control Apply to crawler stage. ♦ bifenthrin (OnyxPro and others)—Restricted use pesticide. (Grp 3) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ dinotefuran (Safari 20 SG)—Check registration status at time of application. (Group 4) ♦ horticultural oil/soap (M-Pede, Ultra-Pure Oil and others)—Some formulations are OMRI-listed for organic production. Christmas tree (Pine)—White pine weevil Pissodes strobi Pest description and crop damage A small brown weevil, roughly 0.25 inch long, with the “snout” typical of other weevils. Wing covers have irregular patches of brown and white scales. Important pest of spruce and pine, occasionally a pest of Douglas-fir. Management—chemical control Apply to the tops to control egg-laying weevils as weather warms in spring. Several applications 3 to 4 weeks apart may be necessary. ♦ bifenthrin (OnyxPro and others)—Restricted use pesticide. (Grp 3) ♦ diflubenzuron (Dimilin 4L, 25W)—Restricted use pesticide. (Group 15) ♦ phosmet (Imidan 70W) (Group 1) Spruce Christmas tree (Spruce)—Cooley spruce gall adelgid Adelges cooleyi Pest description and crop damage Causes “pineapple” galls on spruce, the primary host. See table: Hosts and Symptoms of Major Aphid and Adelgid Pests of Christmas Trees Management—chemical control Apply to control crawler stage, usually when new growth is expanding in spring. ♦ bifenthrin (OnyxPro and others)—Restricted use pesticide. (Grp 3) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ dinotefuran (Safari 20 SG)—Check registration status at time of application. (Group 4) ♦ imidacloprid (Admire Pro, Prey 1.6 and others) (Group 4) ♦ spirotetramet (Ultor, Movento) (Group 23) ♦ sucrose octanoate (SucraShield and others)—Some formulations are OMRI-listed for organic production. ♦ thiamethoxam (Flagship 25 WG) (Group 4) Christmas tree (Spruce)—Spruce aphid Elatobium abietinum Pest description and crop damage Small, dull-green aphid causes extreme needle drop. Aphids appear early in the season (fall to winter months) and may increase rapidly during March and April. See table: Hosts and Symptoms of Major Aphid and Adelgid Pests of Christmas Trees Management—biological control This aphid eludes most predators except the brown lacewing. Management—chemical control ♦ azadirachtin (AzaDirect and others)—Some formulations are OMRI-listed for organic production. ♦ bifenthrin (OnyxPro and others)—Restricted use pesticide. (Grp 3) ♦ chlorpyrifos ( Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ dinotefuran (Safari 20 SG)—Check registration status at time of application. (Group 4) ♦ imidacloprid (Admire Pro, Prey 1.6 and others) (Group 4) ♦ insecticidal soaps and oils (Ecotec, M-pede, Ultra-Pure Oil and others)—Some formulations are OMRI-listed for organic production. Note: Some oils may discolor blue spruce. ♦ pymetrozine (Endeavor) (Group 9) ♦ spirotetramet (Ultor, Movento) (Group 23) ♦ sucrose octanoate (SucraShield and others)—Some formulations are OMRI-listed for organic production. ♦ thiamethoxam (Flagship 25 WG) (Group 4) F6 PNW Insect Management Handbook Christmas tree (Spruce)—White pine weevil Pissodes strobi Pest description and crop damage A small brown weevil, roughly 0.25 inch long, with the “snout” typical of other weevils. Wing covers have irregular patches of brown and white scales. Important pest of spruce and pine, occasionally a pest of Douglas-fir. Management—chemical control Apply to the tops to control egg-laying weevils as weather warms in spring. Several applications 3 to 4 weeks apart may be necessary. ♦ bifenthrin (Brigade 2EC and others)—Restricted use pesticide. (Group 3) ♦ diflubenzuron (Dimilin 4L)—Restricted use pesticide. (Group 15) ♦ phosmet (Imidan 70W) (Group 1) True Fir Christmas tree (True fir)—Balsam twig aphid Mindarus abietinus Pest description and crop damage Small, yellow-green aphids with woolly exudates attack new terminals. See table: Hosts and Symptoms of Major Aphid and Adelgid Pests of Christmas Trees Management—chemical control ♦ bifenthrin (OnyxPro, Sniper and others)—Restricted use pesticide. (Group 3) ♦ carbaryl (Sevin and others) (Group 1) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ dinotefuran (Safari 20 SG)—Check registration status at time of application. (Group 4) Hosts and Symptoms of Major Aphid and Adelgid Pests of Christmas Trees Tree and symptoms Pest Douglas-fir (Pseudotsuga) Aphids without much waxy covering. Producing large amounts of honeydew, which may be attractive to ants and yellow jackets, or covered by sooty mold. conifer aphid (Cinara spp.) “Pepper” flecks (crawlers) on needles in late spring and/or white cottony tufts on needles before budbreak or after about mid-June. Cooley spruce gall adelgid (Adelges cooleyi) True fir (Abies) Aphids without much waxy covering. Producing large amounts of honeydew, which may be attractive to ants and yellow jackets, or covered by sooty mold. Two species, C. occidentalis and C. abietis, are found in noble fir. The former is found typically on the tree bases on 1-3 year old branches and can be quite damaging, the later is a large conspicuous aphid found on the leaders throughout the year. conifer aphid (Cinara spp.) Swelling (gouting) of branch nodes. Very small waxy adelgids may or may not be found. Trunk, branches, or twigs may be covered with white, waxy secretions in heavy infestations. balsam woolly adelgid (Adelges piceae) Twisting of new growth. Small greenish yellow or bluish gray aphids. Wax and honeydew may be present, matting needles together. balsam twig aphid (Mindarus abietinus) Tree above-ground appears stunted and off-color. Below ground there may be colonies of white colored aphids feeding on roots, often tended by ants. conifer root aphid (Prociphilus americanus) Spruce (Picea) Aphids without much waxy covering. Producing large amounts of honeydew, which may be attractive to ants and yellow jackets, or covered by sooty mold. conifer aphid (Cinara spp.) Pineapple-shape galls or cones on branch tips Cooley spruce gall adelgid (Adelges cooleyi) Twisting of new growth. Small greenish yellow or bluish gray aphids. Wax and honeydew may be present as well. balsam twig aphid (Mindarus abietinus) Old (more than 1 year old) needles shed, especially on lower, shaded portions of tree. Aphids peak in late winter (February–March), decline toward summer. Small, green aphids. spruce aphid (Elatobium abietinum) Pine (Pinus) Aphids without much waxy covering. Producing large amounts of honeydew, which may be attractive to ants and yellow jackets, or covered by sooty mold. conifer aphid (Cinara spp.) White flocking on bark of branches and trunk. Trunk may appear “snow covered.” pine bark adelgid (Pinus strobi) F7 PNW Insect Management Handbook ♦ esfenvalerate (Asana XL and others)—Restricted use. (Group 3) ♦ imidacloprid (Admire Pro, Prey 1.6 and others) (Group 4) ♦ insecticidal soaps and oils (Ecotec, M-pede, Ultra-Pure Oil, 440 Superior Oil, and others)—Some formulations are OMRI-listed for organic production. Note: Some oils may cause discoloration. ♦ pymetrozine (Endeavor) (Group 9) ♦ spirotetramet (Ultor, Movento) (Group 23) ♦ sucrose octanoate (SucraShield and others)—Some formulations are OMRI-listed for organic production. ♦ thiamethoxam (Flagship 25 WG) (Group 4) Management—biological control ♦ aphid predators (Aphidoletes aphidimyza, Aphidius spp., Hippodamia spp., Chrysopa spp.)—Consider attracting predators with forage plantings as keeping some species of predators on-site has challenged growers. ♦ Beauveria bassiana (BotaniGard ES) See: Biological control of Nursery Pests Christmas tree (True fir)—Balsam woolly adelgid Adelges piceae Pest description and crop damage Appear as cottony or grayish mass on stems. They produce swelling at nodes and tips and are especially damaging to Fraser fir. See table: Hosts and Symptoms of Major Aphid and Adelgid Pests of Christmas Trees Management—chemical control Apply to control crawler stage around bud break, usually mid-April to early May. ♦ bifenthrin (OnyxPro, Sniper and others)—Restricted use. (Grp 3) ♦ chlorpyrifos (Lorsban Advanced, Warhawk and others)— Restricted use pesticide. (Group 1) ♦ dinotefuran (Safari 20 SG)—Check registration status. (Group 4) ♦ esfenvalerate (Asana XL and others)—Restricted use. (Group 3) ♦ imidacloprid (Admire Pro, Prey 1.6 and others) (Group 4) ♦ insecticidal soap/oil (M-Pede) ♦ spirotetramet (Ultor, Movento) (Group 23) ♦ sucrose octanoate (SucraShield and others)—Some formulations are OMRI-listed for organic production. ♦ thiamethoxam (Flagship 25 WG) (Group 4) Christmas tree (True fir)—Conifer root aphid Prociphilus americanus Pest description and crop damage Tree above ground is stunted and off-color. Below ground colonies of white aphids attached to roots often tended by small ants. In severe cases, replanting may be required as unhealthy trees are slow to recover. See table: Hosts and Symptoms of Major Aphid and Adelgid Pests of Christmas Trees Management—chemical control ♦ spirotetramet (Ultor, Movento)—Appropriate surfactant necessary. (Group 23) ♦ thiamethoxam (Flagship 25 WG) (Group 4) Christmas Tree Export Pests Many insects have export restrictions, but the pests listed below do not cause tree damage so are listed separately. Christmas tree (Export pests)—Slug and snail Various species Pest description and crop damage There is no crop damage, but slugs and snails are hitchhiking pests and restricted at a number of export destinations. Management—cultural control ♦ Shaking prior to loading will remove some. ♦ Minimizing the time trees are in contact with the ground prior to shipping will help limit numbers. Placing trees on pallets and using tarps should help. Management—chemical control ♦ iron phosphate + spinosad (Bug-N-Sluggo) may be used in fields and on landings. (spinosad: Group 5) ♦ metaldehyde baits (Deadline Bullet and others) may be used in landings and right-of-way areas. Lock Out Slug Bait may be used in plantations and on landings in Oregon only. Christmas tree (Export pests)—German yellowjacket Vespula germanica Pest description and crop damage German yellow jacket is an extremely rare hitchhiking pest and restricted in a number of export destinations. Adults have yellow and black marks with a spade shape on the 1st abdominal segment and black spots down the sides of the 2nd to 5th segments. Easily confused with common yellow jacket. Management—cultural control ♦ Shaking prior to loading will remove some yellow jackets. ♦ During harvest, close doors on trailers when not loading and place netting over stacks of trees in loading sites. Management—chemical control ♦ Spot treating nests with aerosol sprays and trapping with heptyl- butyrate traps early (March) will help control yellow jackets. Christmas tree (Export pests)—Exports to Mexico Management—chemical control The regulations for tree imports into Mexico are prescriptive and state: “A pesticide treatment is required 3 to 6 weeks prior to harvest using one of the following insecticides: permethrin at 36.8% active ingredient (ai), esfenvalerate at 8.4% ai or bifenthrin at 7.9% ai in accordance with doses recommended on the label….” Check export regulations at harvest time as these may be phased out. The pesticide label must also allow for the use of the product on Christmas trees. Only 3 esfenvalerate products meet both the ai and registration components of these rules (below). ♦ bifenthrin (7.9%) (Group 3) ♦ No products meet both the Mexico ai and Christmas tree registration requirements. ♦ esfenvalerate (8.4%) (Group 3) ♦ DuPont Asana XL, EPA Reg. No. 352-515 ♦ S-FenvaloStar (LG International), EPA No. 71532-21-3006 ♦ Zyrate, EPA No. 71532-21-83979 ♦ permethrin (36.8%) (Group 3) ♦ No products meet both the Mexico ai and Christmas tree registration requirements. F8 PNW Insect Management Handbook Common Pests of Nursery Crops John Rinehold Latest revision—March 2014 We thank Robin Rosetta for significant contributions to previous revisions of this chapter. In all cases, follow the instructions on the pesticide label. The PNW Insect Management Handbook has no legal status, whereas the pesticide label is a legal document. Read the product label before making any pesticide applications. Protect pollinators: See How to Reduce Bee Poisoning from Pesticides. Note: Products are listed in alphabetical order and not in order of preference or superiority of pest control. Not all products listed are registered in all states. Nursery crop pests—Aphids Pest description and crop damage Aphids are small, soft-bodied insects with piercing-sucking mouthparts formed into a long needle- like stylet they hold under their body when not feeding. They are usually identified by host plant, and characters such as color, wing venation, antennae, and cornicals (two tubular structures on the hind section of the aphid). The same species can vary in color, shape, and size depending on the time of the year. Immature nymphs look like smaller versions of adult nymphs. Some aphid species produce waxy strands over their surface. All are soft-bodied insects with a piercing–sucking mouthpart called a stylet. Crop damage includes distorted plant growth, particularly terminals, deposition of a sweet, shiny liquid called honeydew, black sooty mold (which grows on the honeydew), waxy deposits (some species), yellowing, plant galls (on some hosts) and general plant decline. Several aphid species are also vectors of plant diseases, particularly viruses. Biology and life history Most species of aphid have similar life cycles. Aphid females give birth to live offspring asexually most of the year without mating. Aphid populations generally are most abundant during the cooler spring and fall seasons. Populations can build up quickly at that time of year. Aphids usually are found in colonies. In spring and fall, under crowded conditions, or when the nutritional quality of their host plant is reduced, aphids may produce winged adults (alates) which can disperse. In the fall, aphids mate and produce eggs for overwintering, especially in colder climates. Some species of adult aphid overwinter on crops, weeds, or trees. There may be as few as two generations or as many as 16 generations each year, depending on the species and climate. Most aphids are associated with one or several host plants. Some have alternate hosts, overwintering on one host and moving to another as the season progresses. Several species have a wide host range, with many host plants including weed species. Examples of these species include: green peach aphid, Myzus persicae, and cotton or melon aphid, Aphis gossipea. There are aphid species that spend some of their life cycle on the root systems of the host plants. Commonly occurring examples include aphids in the family Pemphigidae which are root aphids on conifers and also spend time on alternate hosts such as poplar or ash. Scouting and thresholds Monitor for aphids on at least weekly during the growing season. Scout for aphids near growing terminals near buds and fruit clusters, and leaf undersides, particularly alongside leaf veins. White cast skins, shiny honeydew, black sooty mold, and misshapen terminals are good indicators of aphid presence. Yellow sticky traps and yellow pan traps can help monitor flights of adults. Look for signs of natural enemy activity, including predators and parasites. The bodies of parasitized aphids, called mummies, will look slightly swollen brown or black, sometimes with an exit hole made by tiny wasps. Management—biological control See also: Biological Control of Nursery Pests Management—cultural control A strong spray of water alone often effectively removes aphids. Control of associated ant species which move and protect aphids from their naturally enemies may provide additional control of the aphid populations. Aphid populations tend to be higher in plants that are fertilized liberally with nitrogen and heavily watered, as this produces flushes of succulent growth. Avoid excessive watering, and use slow-release forms or organic sources of nitrogen. Management—chemical control See also: Chemical Control of Nursery Pests There are a variety of chemical tactics available for these soft- bodied insects including relatively low toxicity contact products including soaps, oils, and botanicals. Good coverage with contact pesticides is essential. Also available are very selective chemical tools such as insect growth regulators and active ingredients with novel modes of actions such as pymetrozine (Endeavor) which disables the sucking mechanism of the aphids. Kaolin clay is used as a protective barrier and is best applied prior to infestations. Microbial pesticides such as those using the fungus Beauvaria bassiani (Botanigard, Naturalis O) generally benefit from higher levels of humidity such as can be found during the spring and fall and in many protected systems. Systemic insecticides are particularly useful when contact is difficult and to protect new growth over time. Broad spectrum insecticides are generally less IPM compatible but may be useful when multiple types of insects must be treated. Nursery crop pests—Leafminers Pest description and crop damage There several different types of leafminers, including mines made by the larval stages of flies, moths, sawflies, and beetles. Damage from leafminer feeding occurs as the larvae feeds between the upper and lower epidermis of leaves or stems. Mines start as small round puncture wounds. Some mines with a long winding trail (serpentine mines) through the leaf which gradually expands. Other mines are formed as a larger feeding area called a blotch mine. Sawflies—The adult sawfly insects are generally small thick- waisted wasps, often black and about 0.25 inch long. The larvae are small, and light colored. The larvae feed between epidermal layers, creating large dark blotches in the leaves. After the insects leave, the affected areas turn light brown and crinkle. Aside from the effects on the appearance of the foliage, some defoliation and weakening of the tree can occur. Moth larvae—Lepidopteran larvae in the moth family Tenthredinidae are commonly leafminers. Larvae of Phyllonorycter species form tentiform (slightly puffed out “tent-like” mines) on many hosts including willows, poplars, apples, and hackberry. F9 PNW Insect Management Handbook Additional moth leafminer species include lilac leafminer, Caloptilia syringella and needleminers on pines. Fly larvae—Many dipteran leafmining larvae in the fly family Agromyzidae. These include Liomyza, tiny yellow and black flies whose larvae mine leaves on chrysanthemums. Other dipteran leafminers include birch leafminer, Fenusa pusilla, and leafminers on elm, hawthorn, and alders. Beetle larvae—An example of a beetle leafminer is the European elm flea beetle, whose larvae feeding starts as small serpentine mines later forming blotch mines. Biology and life history Sawflies—Adults first appear in spring, when leaves are partly formed. The females lay eggs on newly expanding leaves, after the eggs hatch they mine out the middle layer of the leaf forming a blotch mine. After 2 to 3 weeks, the larvae drop to the ground and pupate. There are normally one generation per year. Moth larvae—Many of these leafminers have two generations per year. Fly larvae—The female leafminer flies insert their eggs (oviposit) inside the leaves. The eggs hatch and the larvae feeds in the mines, chews a hole through the leaf, and drops to the ground to pupate. Scouting and thresholds Monitoring should include direct observation of susceptible plants during the time the adult insects begin activity in the spring and continue on a weekly basis. Yellow sticky cards or homemade yellow sticky traps can be used to monitor for adult fly leafminers. Most leafminer damage does not impact plant health but may affect marketability. Management—biological control Naturally occurring parasitic wasps lay their eggs on or near the larvae in the mines. The larvae from the eggs feed on the leafminer. Management—cultural control Removal and destruction of mined leaves can reduce pressure. Management—chemical control Most sprays are timed to coincide with egg laying by the adult insects, usually on newly expanding leaves. Some control of fly and beetle larvae within mines can be achieved with systemic insecticides such as the neonicotinoids. See also: Chemical Control of Nursery Pests Nursery crop pests—Scale Pest description and crop damage There are two types of scale commonly encountered: hard scale and soft scale. Hard scale tend to be fairly small in size and lie flatter against the stems than do soft scale. Soft scale is often very rounded and will also produce honeydew with its associated black sooty mold. Scale may have only one or multiple generations per year. Scale often comes into nurseries on propagation material. This example shows the importance of inspections and sometimes, quarantine of any new plant material brought into the nursery. Early infestations can often be rogued or pruned out. Biology and life history The life history varies with species, so species identification is needed to determine life cycle. Generally, scale overwinter as eggs or as an immature scale on twigs and branches. If scale overwinter as an immature, they resume feeding in the spring, and eggs are laid later in spring. If scale overwinter as eggs, these hatch in spring, and the young scale (called “crawlers”) migrate through the foliage to feed on the leaves. Most scale insects are female. Mature females are wingless and often secrete a hard shell-like covering for protection. The males are rare, small, non-feeding, and short-lived but look more like other insects as they have wings. With a few notable exceptions, the first immature stage, or the first “instar” females are generally the only stage that disperses on plant material. All other stages remain attached to the plant surface, sessile. Females lay eggs or crawlers under their secreted scale covering or in a cavity under their bodies. Scouting and thresholds Look for scale along stems and leaf undersides. Inspect twigs during the dormant season for scale. Pay particular attention to weak plants. The crawlers are best observed starting in spring with a 10X magnifying glass. Double-sided sticky tape can be used to check for emerging scale crawlers. Management—biological control Check for presence of holes in the scale covers indicating parasitic wasp activity. Ants, fond of honeydew, will fight off scale natural enemies to protect the source. Control of ants may increase biological control. There are several naturally occurring lady beetles that specialize as natural enemies of scale including Chilocorus and Rhizobius. Larvae of green lacewings and other insects are aggressive predators of scale. However, biological control will not necessarily prevent significant scale infestations. ♦ Avoid use of broad spectrum insecticides to preserve natural enemies. Management—cultural control Closely inspect all incoming plant material and plants used for propagation. Pruning and rouging may be an effective tactic in the landscape or on a limited number of nursery plants. As with aphids, avoid excessive nitrogen fertilizer, as this favors population increase. Control associated ant species as they move scale and protect them from natural enemies. Management—chemical control Scale pests are best controlled at the “crawler” stage: the immature, active stage when the insects are most sensitive to insecticides. Spray applications should be timed to coincide with emergence of the vulnerable crawlers. Another tactic is application of systemic insecticides that are drawn into the plant, managing multiple feeding stages of the scale. Time may be needed for some plants to translocate the insecticide to infested parts of the plant. Systemic insecticides are used against many scale species but generally have been less successful with hard scales and pit scales. ♦ Dormant-season oil spray—Apply with enough water to cover the entire tree thoroughly. See also: Chemical Control of Nursery Pests For more information PNW Nursery IPM: A Matter of Scale (http://oregonstate.edu/dept/ nurspest/scale.htm) WSU Extension Bulletin: EB1552E: Scale Insects on Ornamentals (http://cru.cahe.wsu.edu/CEPUBLICATIONS/EB1552E/EB1552E. PDF) F10 PNW Insect Management Handbook Nursery crop pests—Spider mite Pest description and crop damage Several species of spider mites can cause damage in deciduous ornamentals. Appearance of these mites varies with the species, although all are 0.02 inch or smaller. Adults and nymphs can be yellowish, greenish, or reddish brown, depending on species. Mites damage plants by feeding on leaves, which causes stippling, bronzing, and possibly leaf drop. The reduction in photosynthesis causes loss of vigor. The most common pest species of spider mite on conifers is spruce spider mite. It can cause damage on a wide range of conifers. Adults and nymphs can be yellowish, greenish, or reddish brown. Mites damage plants by feeding on leaves, which causes stippling, bronzing, and possibly needle drop. Webbing occurs with high populations. The reduction in photosynthesis causes loss of vigor. Biology and life history Most mite species share a similar life cycle. The majority of twospotted spider mites overwinter as adult females. Spruce spider mites, which are commonly found on conifers, overwinter in the egg stage. Mites become active in the spring. There may be eight to ten overlapping generations per year. Spruce spider mites overwinter as eggs laid at the base of needles or scales. Mites become active in the spring, usually around mid-April. There may be eight to ten overlapping generations per year. Spruce spider mite is a cool season mite with greatest rates of egg laying during the spring and fall. Scouting and thresholds Observe the leaves for mites and webbing and check for the number of pest and predator mites. Tapping branches over a piece of white paper indicates numbers of mites present. Look for evidence of natural enemy activity. Management— cultural control Suppression of broadleaf weeds such as mallow, bindweed, white clover, and knotweed with cultivation or grasses may reduce mite numbers. Wash mites from the tree with a strong stream of water. This also dislodges dust and dirt, which favor an increase in mite numbers. Water trees properly, as drought-stressed trees are more susceptible. Avoid excessive nitrogen applications, as this encourages mites Management—biological control See also: Biological Control of Nursery Pests Management—chemical control See also: Chemical Control of Nursery Pests Using an ovicide-larvacide in early spring can give good suppression of this mite. For more information Johnson, W.T. and H.H. Lyon (1991), Insects That Feed on Trees and Shrubs, 2nd ed., Cornell University Press (p.472-477). PNW Nursery IPM: Spruce Spider Mite (http://oregonstate.edu/ dept/nurspest/spruce_spider_mite.htm) PNW Nursery IPM: Biological Control of Twospotted Mite (http:// oregonstate.edu/dept/nurspest/two-spottedmite.htm) Nursery crop pests—Weevil Pest Description and Damage Black vine weevil is not always the most common weevil to infest landscape plants. In several landscapes in Oregon, the strawberry root weevil and obscure root weevil were dominant, and in Washington often the clay-colored weevil and species of the native woods weevils are the dominant species in many landscapes. Other species are also present in PNW states (see below). In Washington there are 16 species that have been found on a variety of plants in landscapes. In Oregon, there are several additional species, including Plinthodes tineatus and Otiorhynchus décoratus. It is important to identify the species of root weevil infesting plants (see descriptions below) because of variations in life cycle and susceptibility to pesticides. In the early 1970s, this handbook recommended aldrin, dieldrin, heptachlor and chlordane for the introduced weevils, and malathion and diazinon for native woods weevils. Adult weevils are small dark beetles with a snout (rostrum) and elbowed antennae. They cannot fly so distribution is through migration or movement of infested pots, soil or debris. Also, the adults of most of the species are all females and capable of laying eggs after a period of feeding to mature their ovaries. They are slow moving and should not be confused with swifter predacious ground beetles. Larvae, found around roots, are C-shaped, legless, and white with tan heads, up to 0.5 inch in size. All species are quite similar in appearance and habits of feeding on root hairs, larger roots and root crown. Adult weevils are night feeders that mostly remain in the soil or in debris at the base of the plant during the day, then climb up to feed on leaves at night. Look for ragged notches on the edges of leaves, or flower petals. Black Vine Weevil (Otiorhynchus sulcatus) — One of our largest root weevils (8–11 mm), this species is black with yellow patches of hairs and smooth rounded tubercles on the thorax. Weevils overwinter as larvae in the soil and adults emerge in early June. A few adults are active in winter months in milder climates. In June, larvae pupate, and adults emerge. Eggs are laid singly or in small clusters in or on the soil from June to September. Strawberry root weevil (Otiorhynchs ovatus) —This 4–6 mm, reddish-black to black, shiny weevil has reddish legs; it appears smooth but on magnification has small hairs and pits. Adults emerge in mid June but some overwinter in warmer climates. Barypeithes pellucidus — One of the smallest weevils (2–4 mm), this weevil looks like a tiny strawberry root weevil but is thinner in the side profile and has a soft “down” hairs; one of the few root weevils with males and females (often in copula). Lilac or privet weevil (Otiorhynchus merdionalis) —This weevil is the most common species in eastern Washington and known from collections in E. Oregon. It is 8-9 mm with both males and larger females (often found in copula). They appear uniformly blackish and shiny. Rough strawberry root weevil (Otiorhynchus rugosstriatus) — This species is 6–8.5 mm, and a uniformly a dark mahogany color (reddish brown) with a “matte finish” It is distinguishable by the squared shape of the elytra when viewed from above and short stiff hairs (just barely visible in the outline of the elytra). Clay colored weevil (Otiorhynchus sngularis) —This species is one of the most numerous in W. Washington landscapes. It is 6–9 mm, mottled brown (tan and brown scales) with scales on legs; there are no hairs on elytra or thorax, the underside is shiny dark brown. It is the earliest to emerge in spring, often in April. F11 PNW Insect Management Handbook Otiorhyncu raucus — This recent arrival in Oregon and Washington looks slightly shorter and broader than clay colored weevil, overall light brown with a darker thorax. The thorax has fine setae; underside dull brown rather than shiny beneath. Emerges in early spring. Dark-eyed weevil (Sciaphilus speratus) —Another relative newcomer to landscapes, this slightly iridescent golden weevil has a distinctive dark eyes and dark stripe across the elytra. Nut leaf weevil (Strophosoma melaogrammum) —This 4.5–6 mm weevil is a relative newcomer to landscapes. It is slightly iridescent with coppery-brown scales and a distinctive partial dorsal stripe between the elytra. It is a voracious feeder with a somewhat distinctive feeding pattern, often a “maze” of channels from the leaf edge. It is most commonly found in the fall and spring. Obscure root weevil (Sciopithes obscurus) —This native species is diurnal and is more abundant in wooded areas, and in Oregon. It is 3–6.6 mm, is grayish with brown markings with a distinctive V-shaped line at the declivity (rump). Gr...