Integration of Behavioral, Biological, and Reduced-Risk Chemical Approaches into a Sustainable Insect Management Program for Cranberries

Integration of Behavioral, Biological, and Reduced-Risk Chemical Approaches into a Sustainable Insect Management Program for Cranberries

Summary

This project proposes to develop a biorational integrated pest management program comprising disruption of mating with sex pheromones for Sparganothis fruitworm management, biological control of spotted fireworm, with Trichogramma egg parasitoids, and control of lepidopteran larvae with a reduced-risk insecticide, tebufenozide. The feasibility and cost-effectiveness of an integrated program of insect pest management involving this suite of soft insect suppression tactics have been evaluated on grower fields in New Jersey and Massachusetts. Work completed so far under this project has directly contributed towards the registration of a Sparganothis fruitworm mating disruption product and tebufenozide for lepidopterous pest management in cranberries.

Objectives
To develop microencapsulated formulation of E11-tetradecenyl acetate for disrupting mating in Sparganothis fruitworm.

To evaluate the potential of the egg parasitoid, Trichogramma minutum, in managing the populations of spotted fireworm.

To assess the effects of application method, rate, and pest development stage on toxicity of tebufenozide.

To compare the efficacy and cost-effectiveness of new and traditional insect management methods.

Methods
Objective 1: During the 2000 season, we initiated large-scale field trials in Massachusetts to demonstrate the feasibility of managing Sparganothis fruitworm with applications of microencapsulated formulation of the major sex pheromone component (E11-14:Ac). Eight paired field sites were set up with 16 participating growers and over 200 treated acres. The sites, averaging 26.7 acres, were paired and assigned either the treatment (pheromone) or the control (no pheromone). When Sparganothis moth catch began, pheromone was applied by chemigation at 25 g a.i./acre. For each treated or control bog, berry samples from 2 sq ft were removed from each treatment area and inspected for Sparganothis damage.

Objective 2: Work under this objective has been completed during 1998 and 1999 field seasons. No new work has been undertaken during the 2000 field season.

Objective 3: This season, we compared the residual toxicity of Confirm 2F applied with and without Latron B-1956 and Bond (sticker) against neonate larvae of Sparganothis fruitworm. All treatments were applied with a CO2 pressurized tractor-drawn R&D boom sprayer. Foliage was collected from each treatment/replicate on 0, 3, 6, and 10 days following treatment application for a laboratory bioassay. Mortality was recorded 14 days after initiation of bioassay.

Objective 4: The cost-effectiveness and efficacy of mating disruption and mating disruption with Confirm 2F application was compared with a standard program of applying Lorsban 4E for the management of fruitworm pests in New Jersey. Three pairs of plots (replicates), each between 28 acres and 39 acres in size, were either treated with pheromone or with Lorsban 4E. A subset of plots (10–12 acres) that were treated with pheromone was also treated twice with Confirm 2F, on June 30 and July 8. Formulated pheromone was applied by air at 15 g a.i./acre/application on June 12 and June 30.

Results
Objective 1: Of the eight paired sites, fruit damage was lower in six pheromone-treated bogs compared with untreated bogs. At the remaining two sites, fruit damage was greater in the pheromone treated bogs. The Middle France treated area, which experienced higher damage than the untreated area, was adjacent to an untreated bog of 10 acres. This may have contributed to influx of mated females from the adjacent untreated bog, accounting for the lack of reduction in Sparganothis damage at this site. Treated areas realized an average reduction of 4.7% (1.4% compared to 6.1%) in Sparganothis damage, or about $149.07/acre with current prices of $16/barrel (100 lbs of cranberries).

Objective 2: Work under this objective has been completed during 1998 and 1999 field seasons. No new work has been undertaken during the 2000 field season.

Objective 3: Addition of adjuvants, Latron B-1956, and Bond did not increase mortality of Sparganothis fruitworm or residual toxicity over time compared with the application of Confirm 2F alone. Larval mortality among the treatments was not significantly different at 0, 3, and 6 DAT. However, the mortality on 10 DAT was significantly lower compared with mortality on 0 DAT. The waxy nature of cranberry leaves may enhance the adsorption of the formulation, precluding the need for spreader/stickers.

Objective 4: Fruit damage was higher in bogs treated with pheromone alone. Mating disruption with Confirm 2F treatment provided nearly the same level of protection as the OP treatment. However, the cost of mating disruption with Confirm 2F treatment is expected to be $50–$60 higher per acre than OP treatments. These data suggest that Sparganothis fruitworm can be managed effectively with nonorganophosphate strategies. The recent decline in cranberry prices has severely constrained the adoption of more expensive alternatives.

Reported March 2001

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