2013 Navel Orangeworm Insecticide Efficacy Trial (Merced Co.)

We have completed our data analysis of our 2013 navel orangeworm trial from an orchard near Le Grand, CA. Below is the report:

Objective:  To evaluate the efficacy Brigade (bifenthrin pyrethroid), Proclaim (Emamectin benzoate), Brigade+Proclaim, Altacor (rynaxypyr), Entrust (spinosad), Intrepid (methoxyfenocide), and two different rates of Intrepid Edge™ (spinetoram and methoxyfenozide, GF 3028) for control of navel orangeworm (NOW) timed at Monterrey hull-split in California almonds.

Target Pests:  Navel orangeworm, Amyelois transitella.

Application Timing:  Insecticides applied to ‘Monterey’ at approximately 10% hull split  (July 23, 2013).

Target Pest Stage at Application:  Eggs and early larval stages.

Application Methods:  Plot was established as a randomized complete block design with five blocks of a single tree. Nine treatments were applied which include Brigade at 16 oz/acre, Proclaim at 4.5 oz/acre, a combination of Brigade and Proclaim at 16 and 4.5 oz/acre, respectively, Altacor at 4.5 oz/acre, Entrust at 10 fl oz/acre, Intrepid at 16 fl oz/acre, Intrepid Edge™  at 10 and 12 fl oz/acre for the low and high treatment, respectively, and a control. Latron B-1956 was added as an adjuvant to every treatment at 3.2 fl oz for every 100 gallons of water. Treatments were applied using a hand-held spray gun using approximately 2 gallons per tree.

Orchard: ‘Nonpareil’ and ‘Monterey’ orchard at 20 ft x 18 ft spacing, 110 trees per acre, 360 sq ft per tree. The orchard was a fifth leaf almond orchard located near Le Grand, CA. Only ‘Monterey’ trees were treated in this experiment. Nuts were harvested on August 30^th.

Evaluation Methods: Two hundred and fifty (250) nuts were collected and cracked-out for each of five (5) replications, resulting in 1,250 nuts per treatment. Percent damage by larval feeding on kernels was determined per treatment.

Table 1: Treatments and rates  used within the 2013 Navel Orangeworm hull-split trial in Merced County.

* Latron B-1956 was added as an adjuvant at 3.2 fl oz for every 100 gallons of water.

Table 2: Navel Orangeworm (NOW) nut infestation rates among treatments.

¹ Different letters indicate significant differences between treatments (one-way ANOVA, Tukey-Kramer HSD, p < 0.05). Data ArcSin(√(%)) transformed to meet assumption of normality.

A big thanks to Sperling Orchards for hosting this trial.

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