START: 15 JUN 2003 TERM: 14 JUN 2006 GRANT YR: 2003
GRANT AMT: $52,484
INVESTIGATOR: Prokopy, R.; Cooley, D.
PERFORMING INSTITUTION:
ENTOMOLOGY
UNIV OF MASSACHUSETTS
AMHERST, MASSACHUSETTS 01003
REFINEMENT AND DELIVERY OF BIO-BASED APPROACHES TO REDUCING INSECTICIDE AGAINST TWO KEY APPLE PESTS
NON-TECHNICAL SUMMARY: Plum Curculio and apple maggot are key pests of apples in the Northeast. Bio-based approaches to management may reduce insecticide sprays against these pests.
OBJECTIVES: Objectives encompass efforts in both research (year 1) and extension (years 2 and 3). For year 1, objectives aim at refining and finalizing a simple and effective approach to monitoring plum curculio (an odor-baited trap tree approach) and a simple and effective approach to direct behavioral control of apple maggot (deployment of odor-baited spheres). For years 2 and 3, our aim is to validate and demonstrate in 16 commercial orchards in 7 states (CT, MA, ME, NH, NY, RI, VT) the economic and environmental value of a trap tree approach to monitoring plum curculio and a sphere-deployment approach to controlling apple maggot. For both pests, we aim to deliver information to all apple growers in the 7 cooperating states on advantages of these new approaches compared with existing approaches to management.
APPROACH: In year 1, optimizing a trap tree approach for monitoring plum curculio will involve determining the distance over which attractive odor placed in a perimeter-row tree acts to aggregate curculios, and determining the action threshold for spraying perimeter-row apple trees based on percentage of freshly injured sampled fruit on designated trap trees. In year 1, optimizing the pattern of deployment of odor-baited spheres for direct control of apple maggot will involve determining what distance between perimeter-row traps provides an optimal balance between deploying fewest numbers of traps and achieving effective control (to be accomplished using a ranking system for assigning distance between traps according to the orchard architecture parameters of tree size, tree cultivar and nature of surrounding habitat). In years 2 and 3, effectiveness of an optimal trap tree approach to determining need and timing of insecticide use against curculios will be compared with existing approaches based on calendar-driven sprays or heat unit accumulation models. In years 2 and 3, effectiveness of an orchard-architecture-based ranking system for deploying spheres for apple maggot control will be compared with existing approaches based on calendar-driven sprays or monitoring-trap capture-driven sprays.
PROGRESS: 2003/10 TO 2004/09
In 2004, new approaches for managing plum curculio and apple maggot were successfully
tested. For plum curculio (PC), perimeter-row trap trees were baited with grandisoic
acid plus benzaldehyde to indicate fresh injury levels by PC and to determine
need and timing of sprays against over-wintered PCs. The combined bait resulted
in 20 times more damage by PC to fruit on a single perimeter-row sentinel tree
than on un-baited trees, thereby greatly reducing sampling time. The effectiveness
of the trap tree approach was compared with existing approaches based on calendar-driven
sprays or heat-unit-accumulation models. Each of the 14 orchard blocks in MA
was divided into 3 plots. Plot A received 3 whole-block applications of insecticide
(at petal fall + 2 covers). Plot B received a whole-plot spray at petal fall,
followed by one whole-plot cover. A second whole-plot cover was dependent upon
a Degree-Day model. For plot C, after a whole-plot spray at petal fall, any
later sprays were applied only to peripheral rows 1 and 2, based on the presence
of 1 fresh PC injury in 25 fruit sampled on a trap tree. Efficacy of each method
was assessed by extensive fruit sampling in early July and 1 week before harvest.
PC injury was low for C plots as well as for the other management tactics (1.0-1.4
% injury). A 35% reduction in insecticide use was achieved in Plot C for PC
compared to Plot A. For apple maggot (AM), an improved pesticide treated sphere
and a method for calculating how many spheres to place on the perimeter a block
of trees were tested. The placement method used an index developed from 4 variables:
size of orchard trees, quality of pruning, cultivar composition and nature of
bordering habitat. In 2003, this approach reduced the number of spheres needed
by 40 %. All plots received 4 un-baited sticky spheres to estimate penetration
of AM adults into the block. These spheres were inspected weekly. At harvest,
900 fruit per plot were sampled for AM injury. Management of AM in Plot A consisted
of 3 calendar-driven applications of insecticide to entire plot (mid-July, early-August,
mid-August). Insecticide application in plot B to entire plot was driven by
accumulation of AM on the 4 un-baited sticky red monitoring traps (threshold:
8 AM/4 traps). For direct trap-out control of AM in Plot C odor-baited pesticide-treated
spheres were deployed on perimeter trees of all 4 sides. The new Pesticide-Treated
Sphere (PTS) was composed of a contoured compressed top cap bearing sugar (as
feeding stimulant), spinosad (Entrust), and paraffin wax coupled to a hollow
plastic sphere. Using the new placement system, an average of 22 PTS, each baited
with attractive odor (a 5-component blend), were deployed per plot. In the 14
MA blocks, injury at harvest was low and similar for all 3 management methods
(0.11-0.28 % fruit injured). In addition to the 14 blocks in MA, there were
10 blocks distributed among all the states bordering MA. With the exception
of a few C plots which had higher levels of AM due to pre-existing resident
populations, the results were similar and will be presented in the next report.
IMPACT: 2003/10 TO 2004/09
The odor-baited trap tree approach succeeded in monitoring the seasonal course
of egg-laying by plum curculio and determining need and timing of sprays. After
a whole-orchard application of insecticide shortly after petal fall, later sprays
can be confined to peripheral-row trees driven by a pre-set threshold. Growers
using this approach can expect to reduce insecticide against PC by approximately
35 %. In addition, a trap tree may hold PCs in perimeter-row trees, thus preventing
penetration into interior trees. Growers could achieve 100 % reduction in apple
maggot sprays and have good and affordable control by using the new pesticide-treated
sphere and the new placement method. This could be true particularly for large
blocks of apple trees that are on dwarfing rootstock and are well-pruned. These
results will impact 125 apple growers in MA growing 4,500 acres. At least twice
this number will be influenced in neighboring states.
PUBLICATIONS: 2003/10 TO 2004/09
1. Prokopy, R.J., Jacome, I., and Bigurra, E. 2005. An index for assigning distances
between odor-baited spheres on perimeter trees of orchards for control of apple
maggot flies. Entomol. Exp. et Appl. (accepted).
2. Prokopy, R.J., Jacome, I., Gray, E., Trujillo, G., Ricci, M., and Pinero,
J.C. 2004. Using Odor-baited trap trees as sentinels to monitor plum curculio
(Coleoptera: Curculionidae) in apple orchards. J. Econ. Entomol. 97: 511-517.
PROJECT CONTACT:
Name: Cromack, P.
Phone: 413-545-5913
Fax: 413-545-1977
Email: pcromack@nre.umass.edu