Control of Navel Orangeworm in Almonds Using Insecticides and Assessing Spray Coverage
Commodity Protection and Quality
2011 Annual Report
1a.Objectives (from AD-416)
Investigate the length of persistence of the new soft insecticides in pistachios that target navel orangeworm (Amyelois transitella)and assess spray coverage.
1b.Approach (from AD-416)
Almonds will be sprayed by commercial cooperators and collected at intervals over a 30-60 day period. These almonds will be challenged in the lab by infesting them with known numbers of eggs and assessing adult emergence. Samples will be taken from the hull and environment and analyzed to determine insecticide residue, which will be linked to the success of the bioassays. Additional experiments conducted in the field will assess insecticide coverage using sentinel eggs and spray cards.
This Trust Agreement was established to support Objective 2.B of the parent project, reducing insect pest populations to reduce the need for post harvest treatment as well as promoting the use of selective rather than broad spectrum insecticides to control navel orangeworm. Insecticide spray coverage in almonds using pinned navel orangeworm egg strips containing a known number of eggs was evaluated. The strips were collected one day after exposure, placed on diet and incubated for 3 weeks at 80°F. Control egg strips were placed on unsprayed nuts, incubated for 7 days and then hatch was assessed. The combined ovicidal and neonate larvicidal activity of the insecticides Intrepid and Brigade were determined. Brigade was the most toxic to eggs although Intrepid also produced more than 99% egg mortality in some trials. A second study evaluated the spinosad insecticide Delegate. This chemical was less toxic to eggs than Intrepid or the anthranilic diamide Altacor.