Effectiveness of biobased and chemical insecticide in controlling hemipteran pests in California almond orchards

Monday, November 11, 2024

8:48 AM – 9:00 AM MST

Location: Phoenix Convention Center, 226 B, PCC

Presenting Author(s)

CV

Chang Vue

University of California
Modesto, California

Co-Author(s)

MG

Mahesh Ghimire

Assistant Specialist
University of California
Modesto, California
JR

Jhalendra P. Rijal (he/him/his)

IPM Extension Entomologist
University of California
Davis, California

Hemipteran pests pose a significant challenge across California almond orchards. Specifically, these pests include the Brown Marmorated Stink Bug (BMSB), Halyomorpha halys (Stål), the leaffooted plant bug (LFB), Leptoglossus phyllopus (Linnaeus), and the green stink bug (GSB), Chinavia halaris (Say). Early-season feeding by these Hemipterans can lead to issues such as gummosis, substantial nut abortion, and the dropping of young nutlets. Late-season infestations result in necrotic kernels. Almond growers heavily rely on insecticides to control Hemipteran pest populations due to their ability to develop resistance to insecticides. With few alternative methods available, we tested the potential of biobased insecticides and compared them with two commercial standards to manage these Hemipteran pests. In total, seven biological insecticides were tested: Kaolin, two strains of Burkholderia spp (Venerate XC and MBI-306), Strain A396, soybean corn oil, essential oil, Azadirachtin combined with neem oil, and Beauveria bassiana strain GHA. Additionally, two commercial standard insecticides, Bifenthrin and Indoxacarb, were included, along with an untreated control. Treatments were applied to three trees, with a total of four replications or blocks. The first application was administered on April 17th, 2024, the second on April 29th, 2024, and the final application on May 8th, 2024. Evaluation involved visually spotting any Hemipteran pests after the last application and counting the total number of gumming fruits. Later in the season at harvest, 75 almond nuts were collected from each subsample within each experimental unit across all four replications. These nuts were then hand-cracked and assessed for percent damage.