Pear Psylla Phenology Model

Dormant, 75 – 100 PDD

Conditions:

• Pear psylla: winterform adults are colonizing orchards. Egg lay is starting on woody areas around buds.
• Natural enemies: Trechnites wasps are overwintering in parasitized pear psylla nymphs, Campylomma are overwintering as eggs under bark scales, and Deraeocoris adults are present.

75-100 PDD Conventional Management:

• Pear psylla: spray a particle film as soon as you can after 75 PDD or March 1 (whichever is earlier) to deter pear psylla adult colonization and eventual egg laying. Particle films (Surround CF or Celite 610 at 50 lb/acre) reduce pear psylla adult colonization and egg lay by 80–99%. This reduces pear psylla pressure substantially for the entire first generation. Adding a spreader sticker increases the residual effectiveness of particle films. Mix particle films carefully and clean filters frequently to avoid clogged filters and nozzles.
• Pear psylla/mites: lime sulfur can suppress pear rust mites, spider mites, and pear psylla adults. Wettable sulfur is effective against mites but is less effective against pear psylla than lime sulfur.

75-100 PDD ORGANIC Management:

• Pear psylla: spray a particle film as soon as you can after 75 PDD or March 1 (whichever is earlier) to deter pear psylla adult colonization and eventual egg laying. Particle films (Surround CF or Celite 610 at 50 lb/acre) reduce pear psylla adult colonization and egg lay by 80–99%. This reduces pear psylla pressure substantially for the entire first generation. Adding a spreader sticker increases the residual effectiveness of particle films. Mix particle films carefully and clean filters frequently to avoid clogged filters and nozzles.
• Pear psylla/mites: lime sulfur can suppress pear rust mites, spider mites, and pear psylla adults. Wettable sulfur is effective against mites but is less effective against pear psylla than lime sulfur.

75-100 PDD Not recommended (Conventional and ORGANIC):

• Malathion (Malathion 5EC) is highly toxic to pear psylla, but it has a short residual and pear psylla adults will continue spring migration into orchards after the spray. Malathion is highly toxic to natural enemies overwintering in orchards such as Campylomma, Trechnites, Deraeocoris, and lady beetles.
• Lambda-cyhalothrin (Warrior II) and other pyrethroids are not effective against pear psylla and are highly toxic to all natural enemies.
• Particle Films to Avoid: Cocoon (kaolin) and Microna (calcium carbonate) are not labeled for use as pesticides, and therefore cannot be used in place of Surround CF/WP or Celite 610 for control of pear psylla. Cocoon and Microna can be used for non-insecticidal purposes in orchards, but be advised, despite their similar appearance to Surround and Celite, they do not provide control of pear psylla.

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Popcorn, 350 PDD (see photo)

Conditions:

• Pear psylla: Pear psylla adults are laying eggs on separated flower pedicels and leaves. Flower buds have closed white petals.
• Natural enemies: Trechnites wasps are overwintering in parasitized pear psylla nymphs, Campylomma are overwintering as eggs under bark scales, and Deraeocoris adults are present.

350 PDD Conventional Management:

• Pear psylla:
  • The insect growth regulator pyriproxyfen (Esteem 35WP) will sterilize pear psylla adults and have little effect on natural enemies. Only two sprays of pyriproxyfen are allowed per year and must be spaced at least 14 days apart.
  • Other selective materials such as Cinnerate, azadirachtin (Aza-Direct or Neemix 4.5), diflubenzuron (Dimilin 2L), or buprofezin (Centaur WDG) can be used instead of pyriproxyfen if the 14-day window is not met or you wish to save pyriproxyfen for later.
  • If pressure remains high (2 or more adults per tray), a particle film (Surround CF or Celite 610) spray just before bloom renews the particle film residues to repel pear psylla adults from trees. If two particle film sprays have already occurred, lower rates can be used. There is no evidence that particle films sprayed before bloom will affect honey bee pollination in pears. There is also no evidence that particle films inhibit the action of pesticides.
• Pear psylla/mealybug: buprofezin (Centaur WDG), aids in both pear psylla and mealybug suppression at popcorn.

350 PDD ORGANIC Management:

• Pear psylla: If pressure remains high (2 or more adults per tray), a particle film (Surround CF or Celite 610) spray just before bloom renews the particle film residues to repel pear psylla adults from trees. If two particle film sprays have already occurred, lower rates can be used. There is no evidence that particle films sprayed before bloom will affect honey bee pollination in pears. There is also no evidence that particle films inhibit the action of pesticides.
• Pear psylla/mealybug/scale: Use Cinnerate or azadirachtin (Aza-Direct or Neemix 4.5) to increase pear psylla adult suppression if needed and suppress mealybug and scale.

350 PDD Not Recommended (Conventional and ORGANIC):

• Avoid using broad spectrum insecticides like acetamiprid (Assail 70WP), tolfenpyrad (Bexar), malathion (Malathion 5EC), novaluron (Rimon 0.83EC), or lambda-cyhalothrin (Warrior II) because they will harm natural enemies and pollinators, which are abundant as flower petals open.

• Particle Films to Avoid: Cocoon (kaolin) and Microna (calcium carbonate) are not labeled for use as pesticides, and therefore cannot be used in place of Surround CF/WP or Celite 610 for control of pear psylla. Cocoon and Microna can be used for non-insecticidal purposes in orchards, but be advised, despite their similar appearance to Surround and Celite, they do not provide control of pear psylla.

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900 PDD

Conditions:

• Pear psylla: First generation hardshells are the dominant life stage, but summerform adults and eggs will increase over the following weeks. Young nymphs will start to increase but may not be detectable for two or more weeks depending on weather and suppression of the previous generation.
• Natural enemies: Campylomma nymphs, Deraeocoris adults, green lacewing Chrysoperla carnea may be present if broad-spectrum sprays are avoided.

 900 PDD Conventional Management:

• Pear psylla:
  • Applying a particle film (Surround WP or Celite 610 at 50 lb/acre) repels emerging summerform pear psylla adults from trees, preventing egg lay. Adding a spreader sticker increases the effectiveness and longevity of particle films. Mix carefully and clean filters and nozzles frequently. Be prepared to apply another particle film at 1200 PDD.
  • Spirotetramat (Ultor or Movento) is a systemic insecticide that will reduce survival of upcoming generation of nymphs. This material works best when two applications are made, so a second application can be made 14 days later, at around 1200 PDD. Spirotetramat can only be applied twice per season, and applications must be at least 14 days apart.
• Codling moth/pear psylla/mites: use 1% oil, methoxyfenozide (Intrepid 2F), or chlorantraniliprole (Altacor) to kill codling moth eggs. Oil also increases suppression of psylla and mites.
• Mites: If spider mites are found in low numbers, give predators time to suppress them. In areas where mites are becoming a problem (pear rust mite or spider mites) selective miticides such as fenbutatin (Vendex 50WP), spirodiclofen (Envidor 2SC), or cyflumetofen (Nealta) are effective and are relatively safe for natural enemies.

 900 PDD ORGANIC Management:

• Pear psylla: Applying a particle film (Surround WP or Celite 610 at 50 lb/acre) repels emerging summerform pear psylla adults from trees, preventing egg lay. Adding a spreader sticker increases the effectiveness and longevity of particle films. Mix carefully and clean filters and nozzles frequently. Be prepared to apply another particle film at 1200 PDD.
• Codling moth/pear psylla/mites: use 1% oil to kill codling moth eggs. Oil also increases suppression of psylla and mites.

 900 PDD Not Recommended (Conventional and ORGANIC):

• Avoid using broad spectrum materials, even if they will kill multiple types of pests. It is critical to use only selective materials to avoid pear psylla and spider mite outbreaks. Avoid acetamiprid (Assail 70WP), tolfenpyrad (Bexar), novaluron (Rimon 0.83 EC), lambda-cyhalothrin (Warrior II), spinetoram (Delegate WG), spinosad (Entrust SC), pyridaben (Nexter SC), and fenpyroximate (FujiMite XLO [Note: FuijiMite XLO is only allowed once per season]).
• For organic, avoid broad spectrum insecticides like spinosad (Entrust SC).
• Most of these materials are not effective against pear psylla now because it is difficult to achieve adequate spray coverage, but easy to harm natural enemy populations.
• Particle Films to Avoid: Cocoon (kaolin) and Microna (calcium carbonate) are not labeled for use as pesticides, and therefore cannot be used in place of Surround CF/WP or Celite 610 for control of pear psylla. Cocoon and Microna can be used for non-insecticidal purposes in orchards, but be advised, despite their similar appearance to Surround and Celite, they do not provide control of pear psylla.

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1500 PDD or 14 days after 1200 PDD

Conditions:

• Pear psylla: Summerform pear psylla adults and eggs are at their peak and will begin to decrease. Young nymphs are nearing peak and are starting to molt into hardshells.
• Natural enemies: Multiple species may be present, including Deraeocoris nymphs and adults, Campylomma adults and some nymphs, and lacewing Chrysoperla carnea Young earwig nymphs are active on the orchard floor and will begin moving into trees. Second generation Trechnites adults are emerging from parasitized psylla.

1500 PDD Conventional Management:

• Pear psylla:
  • If only one particle film (Surround WP or Celite 610 at 50 lb/acre) was applied after bloom so far, a second (final) application now will repel the remaining summerform adults and prevent further egg lay. Adding a spreader sticker increases the effectiveness and longevity of particle films, but it is essential to mix carefully and clean filters and nozzles frequently. No more than two particle film applications should be made after bloom, as this can increase the risk of mite outbreaks.
  • Spirotetramat (Ultor or Movento), is a systemic insecticide that kills young nymphs after they hatch. If only one application has been made and it has been 14 or more days, a second can be applied now to suppress the ongoing generation of nymphs.
  • If pear psylla pressure is still high, adding selective insecticides such as diflubenzuron (Dimilin 2L), Cinnerate, or azadirachtin (Aza-Direct or Neemix 4.5) can increase suppression. Do not use azadirachtin products on Comice pears.
• Codling moth: If in a high-pressure area for codling moth, selective insecticides such as granulovirus (Cyd-X HP) or diflubenzuron (Dimilin 2L) will help.
• Mites: If spider mites are found, give predators time to suppress them. In areas where mites are becoming a problem (pear rust mite or spider mites) selective miticides such as fenbutatin (Vendex 50WP), spirodiclofen (Envidor 2SC), or cyflumetofen (Nealta) are effective and are relatively safe for natural enemies.

1500 PDD ORGANIC Management:

• Pear psylla:
  • If only one particle film (Surround WP or Celite 610 at 50 lb/acre) was applied after bloom so far, a second (final) application now will repel the remaining summerform adults and prevent further egg lay. Adding a spreader sticker increases the effectiveness and longevity of particle films, but it is essential to mix carefully and clean filters and nozzles frequently. No more than two particle film applications should be made after bloom, as this can increase the risk of mite outbreaks.
  • If pear psylla pressure is still high, adding selective insecticides such as diflubenzuron (Dimilin 2L), Cinnerate, or azadirachtin (Aza-Direct or Neemix 4.5) can increase suppression. Do not use azadirachtin products on Comice pears.
• Codling moth: If in a high-pressure area for codling moth, selective materials such as codling moth granulovirus (Cyd-X HP) will help control codling moth.
• Codling moth/pear psylla/mites: use 1% oil to kill codling moth eggs. Oil also increases suppression of psylla and mites.

1500 PDD Not Recommended (Conventional and ORGANIC):

• Avoid using broad spectrum materials, even if they will kill multiple types of pests. It is critical to use only selective materials to avoid pear psylla and spider mite outbreaks. Avoid acetamiprid (Assail 70WP), tolfenpyrad (Bexar), novaluron (Rimon 0.83 EC), lambda-cyhalothrin (Warrior II), spinetoram (Delegate WG), spinosad (Entrust SC), pyridaben (Nexter SC), and fenpyroximate (FujiMite XLO [Note: FuijiMite XLO is only allowed once per season]).
• For organic, avoid broad spectrum insecticides like spinosad (Entrust SC).
• Most of these materials are not effective against pear psylla now because it is difficult to achieve adequate spray coverage, but easy to harm natural enemy populations.
• Particle Films to Avoid: Cocoon (kaolin) and Microna (calcium carbonate) are not labeled for use as pesticides, and therefore cannot be used in place of Surround CF/WP or Celite 610 for control of pear psylla. Cocoon and Microna can be used for non-insecticidal purposes in orchards, but be advised, despite their similar appearance to Surround and Celite, they do not provide control of pear psylla.
• Do not use particle films past 1500 PDD as they can leave residues on the fruit, and spray coverage is too poor for them to be effective. In addition, no more than two particle films should be used after bloom, as this will increase the risk of mite outbreaks.

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2100 – 2400 PDD

Conditions:

• Pear psylla: Pear psylla second generation young nymphs are decreasing and hardshells are at their peak. Very few adults are present.
• Natural enemies: a mix of species and life stages are present in orchards with selective spray programs.

2100-2400 PDD Conventional Management:

• Pear psylla: You are unlikely to meaningfully suppress pear psylla or mites by using pesticides because pear psylla hardshells are hard to kill, and spray coverage is poor. Sprays now will only give you a natural enemy deficit, setting you up for a summer explosion of pear psylla in their next generation. Instead of spraying, consider honeydew washing.
• Honeydew washing: remove pear psylla honeydew and prevent injury via overhead sprinklers or airblast sprayers with high water volumes (at least 800 gpa). Do not wash more than necessary, as it can increase disease risk. If at least 30% (15 of 50 leaves) have visible honeydew, you should wash. Wash for 12 hours and let dry before scouting again. Continue this process until 2400 PDD.
• Summer pruning can reduce the pear psylla population. Between 2100 and 2400 PDD is a good time for this because you will be removing infested shoots before hardshells produce much honeydew. If only partial pruning is performed, target shoots with the most honeydew. Summer pruning will also improve spray coverage and light penetration into the canopy.
• Mites: If spider mites are found, give predators time to suppress them. In areas where mites are becoming a problem (pear rust mite or spider mites) selective miticides such as fenbutatin (Vendex 50WP), spirodiclofen (Envidor 2SC), or cyflumetofen (Nealta) are effective and are relatively safe for natural enemies.

2100-2400 PDD ORGANIC Management:

• Pear psylla: You are unlikely to meaningfully suppress pear psylla or mites by using pesticides because pear psylla hardshells are hard to kill, and spray coverage is poor. Sprays now will only give you a natural enemy deficit, setting you up for a summer explosion of pear psylla in their next generation. Instead of spraying, consider honeydew washing.
• Honeydew washing: remove pear psylla honeydew and prevent injury via overhead sprinklers or airblast sprayers with high water volumes (at least 800 gpa). Do not wash more than necessary, as it can increase disease risk. If at least 30% (15 of 50 leaves) have visible honeydew, you should wash. Wash for 12 hours and let dry before scouting again. Continue this process until 2400 PDD.
• Summer pruning can reduce the pear psylla population. Between 2100 and 2400 PDD is a good time for this because you will be removing infested shoots before hardshells produce much honeydew. If only partial pruning is performed, target shoots with the most honeydew. Summer pruning will also improve spray coverage and light penetration into the canopy.

2100-2400 PDD Not Recommended (Conventional and ORGANIC):

• Avoid using broad spectrum materials, even if they will kill multiple types of pests. It is critical to use only selective materials to avoid pear psylla and spider mite outbreaks. Avoid acetamiprid (Assail 70 WP), tolfenpyrad (Bexar), novaluron (Rimon 0.83 EC), lambda-cyhalothrin (Warrior II), spinetoram (Delegate WG), spinosad (Entrust SC), pyridaben (Nexter SC), and fenpyroximate (FujiMite XLO [Note: FuijiMite XLO is only allowed once per season]).
• For organic, avoid broad spectrum insecticides like spinosad (Entrust SC).
• Most of these materials are not effective against pear psylla now because it is difficult to achieve adequate spray coverage but easy to harm natural enemy populations.
• Particle films should no longer be used as they can increase the risk of mites and leave residues on picked fruit.

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2900 PDD

Conditions:

• Pear psylla: Third generation adults, eggs, and young nymphs are increasing, but the increase is usually low or undetectable if a selective pesticide program was used. Programs that used multiple broad-spectrum insecticides earlier in the season are at risk of high pear psylla abundance and population growth.
• Natural enemies: A mix of natural enemy species and life stages are present in orchards with selective spray programs.

2900 PDD Conventional Management:

• Pear psylla:
  • Only consider spraying if there are considerable adults present. Less two adults per tray or 1 young nymph per leaf generally results in less than 5% fruit damage. If you have followed a selective spray program, you likely have natural enemies present in your orchard, so it is not necessary to perform preventative sprays.
  • If pear psylla are projected to surpass damage thresholds, use an insect growth regulator, such as pyriproxyfen (Esteem 35WP) or diflubenzuron (Dimilin 2L). Alternatively, the organic insecticides Cinnerate or azadirachtin (Aza-Direct or Neemix 4.5) can also suppress pear psylla. Do not use azadirachtin products on Comice pears.
• Pear psylla/codling moth: diflubenzuron (Dimilin 2L), granulovirus (Cyd-X HP), or 1% oil can also help suppress codling moth but may not be necessary if pressure is low and mating disruption is in place. Spray based on the codling moth model and trap capture.
• Pear psylla/mites: 1% oil will help to suppress pear psylla and mites. If spider mites are found, give predators time to suppress them. In areas where mites are becoming a problem (pear rust mite or spider mites) selective miticides such as fenbutatin (Vendex 50WP), spirodiclofen (Envidor 2SC), or cyflumetofen (Nealta) are effective and are relatively safe for natural enemies.

2900 PDD ORGANIC Management:

• Pear psylla:
  • Only consider spraying if there are considerable adults present. Less two adults per tray or 1 young nymph per leaf generally results in less than 5% fruit damage. If you have followed a selective spray program, you likely have natural enemies present in your orchard, so it is not necessary to perform preventative sprays.
  • If pear psylla are projected to surpass damage thresholds, Cinnerate or azadirachtin (Aza-Direct or Neemix 4.5) can also suppress pear psylla. Do not use azadirachtin products on Comice pears.
• Pear psylla/codling moth: granulovirus (Cyd-X HP), or 1% oil can help suppress codling moth but may not be necessary if pressure is low and mating disruption is in place. Spray based on the codling moth model and trap capture.
• Pear psylla/mites: 1% oil will help to suppress pear psylla and mites.

2900 PDD Not Recommended (Conventional and ORGANIC):

• Avoid using broad spectrum materials even if they will kill multiple types of pests; doing so will eliminate your natural enemies and cause outbreaks of pear psylla and spider mites. Broad spectrum materials to avoid include (but are not limited to) acetamiprid (Assail 70 WP), thiamethoxam (Actara), imidacloprid (Admire Pro, Macho, others), tolfenpyrad (Bexar), novaluron (Rimon 0.83 EC), lambda-cyhalothrin (Warrior II), spinetoram (Delegate WG), spinosad (Entrust SC), pyridaben (Nexter SC), and fenpyroximate (FujiMite XLO [Note: FuijiMite XLO is only allowed once per season]).
• For organic, avoid broad spectrum insecticides like spinosad (Entrust SC).
• Most of these materials are not effective against pear psylla now because it is difficult to achieve adequate spray coverage but easy to harm natural enemy populations.
• Particle films should no longer be used as they can increase the risk of mites and leave residues on picked fruit.

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3500 PDD

Conditions:

• Pear psylla: Third generation young nymphs at peak and hardshells are increasing. However, the increase is usually low or undetectable if a selective pesticide program was used. Programs that used multiple broad-spectrum insecticides earlier in the season are at risk of high pear psylla abundance.
• Natural enemies: All natural enemies and life stages are occurring in selectively sprayed orchards.

3500 PDD Conventional Management:

• Pear psylla: you are unlikely to meaningfully suppress pear psylla or mites by using sprays because pear psylla hardshells are hard to kill, and spray coverage is poor. Sprays now will only give you a natural enemy deficit, setting you up for a late-season explosion of pear psylla. Instead of spraying, consider honeydew washing.
• Honeydew washing: remove pear psylla honeydew and prevent injury via overhead sprinklers or airblast sprayers with high water volumes (at least 800 gpa). Do not wash more than necessary, as it can increase disease risk. If at least 30% (15 of 50 leaves) have visible honeydew, you should wash. Wash for 12 hours and let dry before scouting again. Continue this process until 2400 PDD.
• Pear psylla/codling moth: diflubenzuron (Dimilin 2L), granulovirus (Cyd-X HP), or 1% oil can also help suppress codling moth but may not be necessary if pressure is low and mating disruption is in place. Spray based on the codling moth model and trap capture.
• Pear psylla/mites: 1% oil will help to suppress pear psylla and mites. If spider mites are found, give predators time to suppress them. In areas where mites are becoming a problem (pear rust mite or spider mites) selective miticides such as fenbutatin (Vendex 50WP), spirodiclofen (Envidor 2SC), or cyflumetofen (Nealta) are effective and are relatively safe for natural enemies.

3500 PDD ORGANIC Management:

• Pear psylla: you are unlikely to meaningfully suppress pear psylla or mites by using sprays because pear psylla hardshells are hard to kill, and spray coverage is poor. Sprays now will only give you a natural enemy deficit, setting you up for a late-season explosion of pear psylla. Instead of spraying, consider honeydew washing.
• Honeydew washing: remove pear psylla honeydew and prevent injury via overhead sprinklers or airblast sprayers with high water volumes (at least 800 gpa). Do not wash more than necessary, as it can increase disease risk. If at least 30% (15 of 50 leaves) have visible honeydew, you should wash. Wash for 12 hours and let dry before scouting again. Continue this process until 2400 PDD.

• Pear psylla/codling moth: granulovirus (Cyd-X HP), or 1% oil can help suppress codling moth but may not be necessary if pressure is low and mating disruption is in place. Spray based on the codling moth model and trap capture.
• Pear psylla/mites: 1% oil will help to suppress pear psylla and mites.

3500 PDD Not Recommended (Conventional and ORGANIC):

• Avoid using broad spectrum materials even if they will kill multiple types of pests; doing so will eliminate your natural enemies and cause outbreaks of pear psylla and spider mites. Broad spectrum materials to avoid include (but are not limited to) acetamiprid (Assail 70 WP), thiamethoxam (Actara), imidacloprid (Admire Pro, Macho, others), tolfenpyrad (Bexar), novaluron (Rimon 0.83 EC) lambda-cyhalothrin (Warrior II), spinetoram (Delegate WG), spinosad (Entrust SC), pyridaben (Nexter SC), and fenpyroximate (FujiMite XLO [Note: FuijiMite XLO is only allowed once per season]).
• For organic, avoid broad spectrum insecticides like spinosad (Entrust SC).
• Most of these materials are not effective against pear psylla now because it is difficult to achieve adequate spray coverage but easy to harm natural enemy populations.
• Particle films should no longer be used as they can increase the risk of mites and leave residues on picked fruit.

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