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, methyl bromide alternatives, by reducing insect pest populations to minimize the need for post harvest treatment and promote the use of selective rather than broad spectrum insecticides. Navel orangeworm is the most destructive lepidopteran pest of almonds and pistachios in California. One of the challenges in controlling this pest is effectively covering the tree nuts with insecticides. An ARS scientist at Parlier, in collaboration with scientists from UC Davis, evaluated insecticide spray coverage using experimental spray rigs. Findings to date have quantified the loss of insect control as tree height increases and the importance of keeping tractor speed at 2 mph when applying insecticide. Research is ongoing to evaluate proposed improvements in applicator design as well as quantifying coverage using commercial insecticide application spray rigs. Ultimately, this research will provide data to support the importance of tractor speed as well as the need to develop new strategies to improve insecticide spray coverage above 14 feet.