Skip to main content
ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Commodity Protection and Quality Research » Research » Research Project #446128

Research Project: Improved Control of Navel Orangeworm: Focus on Adjuvants and Application

Location: Commodity Protection and Quality Research

Project Number: 2034-43000-043-070-T
Project Type: Trust Fund Cooperative Agreement

Start Date: Mar 4, 2024
End Date: Mar 3, 2025

This is a proposal intended to improve navel orangeworm (NOW) control by focusing on two components of control strategy, application improvement and improved application speed, with an emphasis on using organosilicone adjuvants and evaluating several methods of ground application and air application. The Objectives are as follows: 1. Determine if switching to organosilicone adjuvants or a methylated organosilicone adjuvant instead of Latron B-1956 can allow an orchard to reduce water volume from 200 gpa to 100 gpa with GUSS autonomous sprayers. Additionally, determine if 80 gpa and an organosilicone adjuvant can work in this system. 2. Quantify the difference between at least two other categories of adjuvant to improve coverage in the upper canopy and duration of control for Air-o-Fan multinozzle sprayers. 3. Obtain additional information on the variability of air application, the effect of reducing spray volume in air application to 10 gpa and increasing the duration of control through adjuvant concentration.

Insecticide coverage will be evaluated using filter paper for contact toxicity bioassay. Duration of control is determined using filter papers placed on hooks at a height of 12-14 feet prior to application and then collected at selected intervals up to 19-21 days. The filter papers are brought back to the laboratory, placed in Petri dishes containing wheat bran diet, and 50 NOW eggs are placed in the center. When the eggs hatch larvae must crawl over the filter paper to get to the diet. When they crawl over the filter paper they contact the insecticide, which causes mortality. The dishes are incubated for 18 days at 80°F and then scored. This is a flexible technique because insecticide can also be extracted from the filter paper to chemically quantify the amount delivered if necessary (not in this proposal). Additionally, pistachios may be collected from the field and challenged with eggs to help determine the duration of control. If necessary, challenge assays will use split pistachios collected from the tree or from bins during harvest. Pistachios will be placed in glass jars, 100-200 pistachios per jar, and egg sheets are placed on the pistachios (4 eggs per nut, 400-800 eggs per jar). The jars are incubated at 80°F for 3.5-4 weeks and then the nuts are removed, and all surviving NOW counted.