Importance of Timing for Codling Moth and Obliquebanded Leafroller Management Vincent P. Jones WSU-Tree Fruit Research and Extension Center Department of Entomology Wentachee, WA
Overview Codling moth Life history Effect of warm years Management targets Mating disruption Horticultural oils, granulovirus Labor intensive methods Timing Traditional versus delayed first cover Insights from models Trap catch Summary OBLR Life history Treatment windows
Life History Overwinter as last instar larvae Pupate in early spring First adults emerge starting at 175 DD from 1 January Tendency for emergence on DD scale to be later when spring and winter are warmer Mate immediately, lay eggs near or on fruit that hatch after 150 DD Have at least 2-3 flights over season 4-5 fold increase in populations per generation Phenology is predictable and detailed on WSU DAS
Effect of warm years Hotter year = more generations = more CM Warm spring = CM emerge earlier on calendar date basis Warm fall = more larvae that escaped diapause in August will make the overwintering stage Hotter year = more larvae in diapause that will emerge next year Hotter years always cause more problems the following year!
Total Larvae/Generation 2011vs. 2015 Konnowac Pass 25761 7317 =3.52 x 19% 4 th generation 27% 3 rd generation Larval Generation
Codling Moth Management Target is the eggs or newly emerged larvae 150 DD length of egg stage is very important MD acts to reduce egg production Works best when it is hot Mode of action is it delays mating Normally apply a pesticide 1-2 times in 1 st generation Developed models to simulate pesticide applications Can apply up to 18 different times in season Organic/conventional materials Can choose residual length, amount of mortality Mixtures of oil + pesticides Run based on weather data
Mating Disruption Flood orchard with synthetic pheromone Dispensers Puffers Males have hard time finding females As delay in mating increases on a DD scale, population growth decreases Makes all other controls better! Prop. of the Control Pop. Growth Rate
Horticultural Oil All eggs contacted affected Egg age not important CM larvae eating oil when entering fruit are often killed ( 30%) Coverage is key Has effects on broad range of pests and easy on most natural enemies Mites Aphids San Jose scale Residue is gone rather quickly ( 1 d)
CM Granulovirus Enters through larval gut Kills larvae slowly, generally in first instar Can allow some stings Can have sub-lethal effects, reducing adult emergence 25% Deactivated by UV in sunlight Re-apply at 5-7 d intervals Often applied with oil
Labor Intensive Methods Banding Target times when larvae are pupating Gen 1 1000 DD, destroy bands by 1350 DD 60% pupae Could do last half as well 1350-1600 DD in high pressure situations Other generations, just add 1000 DD for each generation (e.g., 2000 DD remove by 2350) Fruit stripping Destroy the fruit removed!
Variations on Timing Target is normally egg hatch 3% 425 DD after 1 January (250 DD from 1 st flight) Next spray goes on depending on the residue 1425 DD after 1 January (1250 from 1 st flight) Next spray goes on depending on the residue Issue is with low residual materials Few eggs ready to hatch at 425 DD Residue kills first hatching larvae, but is weak when majority eggs start to hatch Requires at least 2 sprays per generation and materials with 14-17 day residues Leaves last and first part of flight unprotected
Delayed First Cover Timing Apply on oil apply at 375 DD Kills eggs about to hatch and those recently laid Allows a delay of main pesticide by 150 DD (to 525 DD) 150 DD = average length of egg stage Put on sprays with normal intervals based on residues If using Esteem, Intrepid, Rimon apply at 225-325 DD Delay main pesticide until 525 DD Use residue intervals to apply last cover
82% egg hatch 855 DD 22 June 18% egg hatch on weak residue Normal Timing 2.5% egg hatch 425 DD 24 May 36% egg hatch 616 DD 8 June 15 d 15 d 2.5% hatch on no residue
Delayed First Cover Timing Oil 16% eggs laid 0% egg hatch 380 DD 20 May Delayed first cover 17.7% egg hatch 530 DD 1 June Second cover 67% egg hatch 758 DD 16 June 150 DD Length of Egg stage 15 d 15 d 98% egg hatch 1023 DD 1 July
855 DD Residue weak 82% egg hatch 2155 DD Residue weak 95% egg hatch 1815 DD 616 DD 425 DD 1425 DD 15 d 15 d 15 d 15 d Normal Timing
1025 DD Residue weak 760 DD 1905 DD 2235 DD Residue Weak 98% egg hatch 380 DD 530 DD 1380 DD 1530 DD 150 DD 15 d 15 d 150 DD 15 d 15 d Delayed First Cover Timing
Organics with Mating Disruption Oil alone Low pressure sites, 1 st spray at 375 DD, 200 DD intervals Probably don t need sprays in second generation High pressure sites, 1 st spray at 375 DD, 150 DD intervals Virus Use delayed strategy 1 st spray at 375 DD (oil) Virus at 5-7 day intervals throughout 1 st generation ( 950 DD); 4 times Sprays in second generation probably not needed Oil + virus (high pressure sites) Controls both eggs and larvae Probably only need in 1 st generation, 2nd gen can be either oil or virus
Comparison CM treatments & MD Cool Year (2011) 1 st gen only - organic 100
Comparison CM treatments & MD Hot Year (2015) 1 st gen only - organic 100
Comparison CM treatments & MD v2 Hot Year (2015) 1 st gen only - organic 100
Effect of Warm Years on Control Measures Pesticides work best in hotter years Pesticides degrade based on sunlight and on a calendar date basis Hotter years mean that more of the population passes through the stages susceptible to the pesticide for a given residual length Harder to hit the timing targets because even a day or so can allow a significant number of larvae to enter the fruit Mating disruption works best in hotter years MD reduces population growth by delaying mating Mating delay is measured on a DD scale Hotter year means that the same 2 day delay as a cold year can greatly reduce egg production Hotter years also increase the mortality of the moths, so they die sooner, reducing period to lay eggs
Factors Affecting Moth Flight/Trap Catch Wind speed Rainfall Temperature Mating Disruption Bin Piles
How many traps? 1 trap every 2.5 acres; realistically 1 per 5 acres Traps are not attracting moths from long distance CM populations are not uniformly distributed
What to use the traps for CM Pressure in a given block if you have enough traps Use the traps to moderate or intensify spray program Can use with models to get idea of total population Traps do not provide timing information DO NOT USE for gauging when to stop spray program Still catching moths does not mean keep spraying! Can provide information on location of external sources and hotspot locations Defining thresholds is difficult because of MD, type of lures used, external sources, and grower experience
Summary Use Mating disruption Gives season long protection, but weaker in spring and late fall Generally use at least 2 sprays in 1 st generation Use delayed first cover strategy Pesticide timing is crucial More so than material used Use DAS for best timing information Egg stage is 150 DD long This determines re-treatment intervals when using oil Virus has low longevity (5-7 days), but with MD and oil is very effective
Summary (con t) Save Entrust for the very worst situations Reported resistance in leafrollers Harsh on natural enemies In conventional situations, chose between efficacious materials considering effect on natural enemies Use WSU DAS for best timings, efficacy ratings, effects on natural enemies DD models simplifies control and makes the management independent of the seasonal temperature profiles
Oblique-banded leafroller Life history Note on resistance to Bt Pesticide effects models Effect of shoot growth
Leafroller Life History Overwinter as 2nd or early 3rd instar larvae in bark scales and pruning cuts Emerge in spring when tree breaks dormancy Attacks buds, then moves to leaves Pupate in leaves, OW gen adults emerge in June Summer generation larvae feed near tips of shoots Adults of summer generation start in early August Larvae develop up to 3rd instar then move to OW sites Problem is if leaves contact fruit Leafrollers feed on leaves and damage surface of the fruit
A word about resistance to Bt Short residual makes it unlikely to occur in field situations Bt lasts 7 days in field (low selection pressure) Lots of alternate untreated host plants (lowers selection pressure) Lots of dispersal between them (lowers selection pressure) Quality control of Bt and storage is also potential issue Different strains have different activity Only 1 case of a pest developing resistance to foliar applications of Bt (diamond back moth)
Pesticide Effects Models Pesticide effects models show 4 control windows 90 DD larvicide (second most important) Need protection between 90 & 160 DD 720 DD ovicide (oil) least important 900 DD larvicide + oil most important Need protection between 900 & 1450 DD 1800 DD oil + larvicide At least 2 windows (esp. 900 DD) need to be targeted All the programs tested were >2x better than old standard Timing and mode of action (larvicide/ovicide) key to control All conv. pesticides we field tested had comparable activity 85%+ mortality for >55 days in the summer
Patterns of susceptibility 6 locations x 5 years 0.52 0.30 0.30 x 0.52 = 0.156
Susceptibility of OBLR II Timing is key! Length of residue Stages present at application Mixtures give added control at times
Effects of Shoot Growth on Residues and Management Long residual of conventional pesticides Don t expect multiple sprays would be needed EXCEPT biology effects Shoot growth results in unprotected leaves at the tip Leafrollers like to feed on the new growth
Shoot Growth Effects on Altacor Efficacy Summer Spring
Non-Target effects of OBLR treatments P = conv. Larvicide O=oil Bt = Dipel Prev. Standard Low lacewings = more aphids, mites, scales, small leps
Take home message for OBLR Only a few windows in time where management is effective Need to hit at least two of the windows 900 DD and 90 DD are the most important If using Bt, 3-4 applications may be needed 7 days apart Early season conventional sprays reduce lacewing populations Shoot growth limits the effective longevity of residues Use Entrust sparingly and only for high populations Resistance reported Harsh on natural enemies