Progress 06/15/03 to 06/14/06
Outputs
Our intent was to optimize a pesticide-treated sphere (PTS) approach for managing apple maggot(AM) and a trap tree approach for managing plum curculio (PC). These methods combined the biological tools of pheromones, host-plant attractants, visual attraction, scouting methods, and the reduced use of relatively safe insecticides. The ultimate goal was to demonstrate efficacy of these methods over two years in many blocks of apple trees throughout New England and New York. For plum curculio, the effectiveness of an optimal trap tree approach to determine need and timing of insecticide use against PC in comparison with existing approaches based on calendar-driven sprays or heat-unit-accumulation models was tested in 25 blocks of apple trees in 2004 and 21 blocks in 2005. The trap tree approach proved effective in the vast majority of the sites over 2 years. In those few cases where fruit injury was above 1 or 2 %, the cause could be attributed to missing an insecticide
spray, to having intense PC pressure coming from within the orchard block, or to a planting arrangement of very small apple trees. In both years there was a significant reduction in pesticide use (35% reduction between the calendar spray treatment and the trap tree treatment in 2004 and a 30% reduction in 2005). At the same time, fruit injury was equally low in all 3 approaches (0.8-1.5 % in 2004 and less than 1 % in 2005). The trap tree approach works well if the twice-weekly scouting of fresh injury in the trap tree is performed regularly and the grower can respond right away. It is more labor-intensive than the other 2 approaches. For apple maggot, we tested the effectiveness of an orchard-architecture-based ranking system for deploying odor-baited pesticide-treated spheres (PTS) for direct control of AM in comparison with existing approaches to AM control based on calendar-driven sprays or monitoring-trap-capture-driven sprays in the same blocks. The PTS approach proved very
effective in all but 3 of the 24 sites in 2004 (0.2 to 0.9 % fruit injured over all 3 approaches) and in all of the 21 sites in 2005 (0.09-0.23 % fruit injured over all 3 approaches). The 3 instances of inadequate control were due to overwintering populations within the orchard block. This would not have ocurred if the orchard blocks had been under IPM management in 2003. Pesticide reduction was very significant in the IPM blocks (in 2005 a 93 % reduction was seen from calendar sprays to the PTS approach and a 48% reduction from calendar sprays to the monitoring-trap-capture approach). In 2005, the active ingredient in the PTS (spinosad) was reduced 50% from the 2004 level to 0.5% active. The sphere was as effective at the lower rate. The PTS approach is ready for commercialization and widespread use. It will be most cost effective in blocks of apples trees of 10 acres or more.
Impacts
In the Northeastern states, the value of commercial apples exceeds $225 million dollars. Growers in the seven cooperating states (approximately 375 growers) have been able to directly observe the results of this approach to PC and AM management. Cooperating researchers have presented talks to growers in the region and at national meetings. Growers using the trap tree approach can expect to reduce insecticide against PC by approximately 33%. 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. The Northeast represents a major apple production region in the U.S. and many growers can be expected to adopt these approaches.
Publications
- No publications reported this period
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Progress 10/01/04 to 09/30/05
Outputs
In 2005, the project continued to test and demonstrate the use of the trap tree approach for plum curculio and the pesticide-treated sphere approach to apple maggot control. Over all the cooperating blocks, a total of 21 blocks were used. Each block tested the methods on approximately one acre plots of apples in commercial orchards. This was a second year of a two-year research and demonstration trial, and the methods described in the progress report for 10/2003 to 9/2004 were used in 2005, except as noted. PC population pressure was higher across the region in 2005. The advanced methods using the trap tree had less than 1% fruit injury at harvest, comparable to damage in blocks managed with calendar level or basic IPM methods. As in 2004, blocks with dwarf trees had more PC damage in the interior of the block than did blocks with semi-dwarf trees. However, the method still worked at levels comparable to those obtained using conventional and basic IPM approaches. The
success of this method depends on growers responding quickly to the information that is obtained from twice-weekly counts obtained in the trap tree. This method works well if counts are made on schedule and if growers respond to this information by treating as needed. In 2005, the active ingredient for the spinosad was cut 50% from 2004 to 0.5% active. With the lower rate, the pesticide-treated sphere was still as effective as either the conventional or basic IPM treatment. Fruit damage levels in all blocks was kept below 0.3%.
Impacts
In the Northeast states, the value of commercial apples exceeds $225 million dollars. Growers in the seven cooperating states have been able to directly observe the results of this approach to PC and AM management. Cooperating researchers are presenting talks to growers in the region. Growers using this approach can expect to reduce insecticide against PC by approximately 35%. 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. The Northeast represents a major apple production region in the U.S. and the majority would be expected to adopt these approaches.
Publications
- Pinero, J. and R. Prokopy. 2005. Spatial and temporal within-canopy distribution fo egglaying by plum curculios (Coleoptera:Curculionidae) on apples in reation to tress size. J. Entomol. Sci. 40(1): 1-9.
- Rull, J. and R. Prokopy. 2004. Host-finding and ovipositional-boring responses of apple maggot (Diptera:Taphritidae) to different apple genotypes. Envrion. Entomol. 33(6): 1695-1702.
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Progress 10/01/03 to 09/30/04
Outputs
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.
Impacts
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
- 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).
- 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.
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Progress 10/01/02 to 09/30/03
Outputs
For plum curculio (PC) in 2003, in 15 one-acre blocks of apple trees in commercial orchards in MA we established a single tree (= trap tree) baited with benzaldehyde (synthetic attractive fruit odor) released at 40 mg/day plus grandisoic acid (synthetic attractive pheromone) released at 1 mg/day. The trap tree was located at the center of the perimeter-row of a block, about 35 m from either end of the row. Fruit injury by PC adults immigrating from adjacent overwintering sites averaged 8-fold greater on trap trees than on unbaited trees within 31-33 m to either side of trap trees, indicating that trap trees are attractive to PCs over a distance of at least 31-33 m. In 3 1/2-acre plots (60 m wide) in each of 9 other commercial apple orchards, we used appearance of fresh PC injury on a trap tree at the center of the perimeter row of the plot as a guide for need and timing of sprays against PC. Results showed that a threshold of 1 freshly injured fruit proved better than
thresholds of 2 or 4 freshly-injured fruit out of 50 fruit sampled on a trap tree in assuring that plot-wide PC damage would remain below a pre-set economic injury level of 1%. For apple maggot flies (AMF) in 2003, in 12 one-acre plots of apple trees in commercial orchards in MA, we hung varying numbers of odor-baited sticky sphere traps on perimeter row trees on all 4 sides of each plot to intercept immigrating AMF. Distances between spheres (range 5-15 m) on perimeter-row trees were based on a newly-developed formula that incorporated tree size, extent of pruning, tree cultivar and nature of adjacent habitat as distance-determining factors. Performance was assessed on basis of captures of AMF on unbaited monitoring spheres at interior of plots and percent fruit injured by AMF. In 9 of the 12 plots, traps performed as well as grower-applied sprays used in adjacent plots for AMF control. In the other 3 plots, each having large trees, trap performance was less satisfactory.
Impacts
For PC, for the first time, need and timing of spray can be based on a monitoring technique that incorporates an economic threshold: spray when 1 fruit out of 50 fruit sampled on a odor-baited perimeter-row trap tree shows fresh PC injury. For AMF, evaluation of a new approach to determining distances between odor-baited perimeter-row traps that results in use of fewer traps per hectare to achieve direct control showed much promise in 75% of the orchards where tested.
Publications
- No publications reported this period
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