Technology Corner: Spear-Lep w/Vestaron
EDITOR'S NOTE: This entry is the first in a new and (hopefully) ongoing series to highlight new technology related to almond and tree nut production. The question/answer format is set to focus more on the technical aspects and application of the technology. Since we are approaching hull-split, I thought a reasonable place to start would be with Vestaron, a company which recently released a new class of insecticides.Thanks to Noel Cornejo for taking the time to answer my questions.
Question (Q): Spear-Lep is a new group of insecticides that has been shown to be effective on lepidopteran pests, such as peach twig borer, codling moth, and navel orangeworm. What is the active ingredient and how does this product work?
Answer (A): The active ingredient is an insecticidal peptide called GS-omega/kappa-Hxtx-Hv1a. It was carefully optimized to target the nicotinic acetylcholine receptor in the insect nervous system, but at a receptor site distinct from Spinosad and neonicotinoids. The end result is paralysis of the lepidopteran larvae that ingest it.
Q. Is this product directly toxic to insect pests? Or does it have to be consumed? How is the activity on developing larvae (may have been answered above)?
A. For lepidopteran pests Spear works through ingestion. Extensive studies confirm activity against neonates as well as later instars of all species tested to date. At high v/v concentrations, Spear works though topical contact against smaller, soft-bodied pests such as mites, thrips and whiteflies.
Q. How is this product different from what is currently on the market and is there any efficacy data comparisons among the various products on the market?
A. This novel class of insecticidal peptide is the first of its kind. Identified in nature, and then optimized painstakingly in the lab, Vestaron’s peptide insecticides are designed to target neuromuscular receptors proven through the use of conventional insecticides. The Spear peptide – and those that follow in the pipeline – bring novel resistance management options to the grower toolbox, meaning safer and more sustainable solutions with no sacrifice of performance.
Q. What levels of insect control have been observed in research trials and how long after spraying does it control insect pests?
A. More than three years of third-party replicated trials confirm that Spear-Lep achieves levels of control that are similar to or greater than conventional synthetic insecticides. The product’s versatility means a smooth fit into a traditional spray program rotation, or as a standalone product, in 7-14-day spray intervals (Editors note: please see attached files at the end of the entry).
Q. Does this product have to be tank mixed with BT or another insecticide? Is it certified for organic use?
The molecular weight of the Spear peptide is far greater than a traditional small molecule chemical. So “bioavailability” was an early hurdle in product development – how to enable the active ingredient to pass through the gut membrane, into the body cavity, and into contact with receptors in the nervous system. A gut disruptor was the solution. Spear-Lep is therefore applied with a low labelled rate of Bt kurstaki (or other lepidopteran active Bt) that opens pores in the mid gut membrane for the Spear peptide to cross over. Although classified as a bioinsecticide by the EPA, Spear-Lep is not certified for organic use.
Q. Some of the unique features is the short re-entry interval and reduced impact on beneficial predator insects. Does it only target lepidopteran pests, or does it affect thrips or other beneficials? In other words, how many different families of insects may this product affect?
A. Given the size of an insecticidal peptide, the spectrum of activity is essentially controlled by how we address the bioavailability challenge. Relatively low rates of both Spear and Btk mean activity against caterpillars. Non-targets are protected because Btk is only active on leps and the low rate of Spear is sublethal by itself. In a similar fashion, beetle pests can be targeted by Spear teamed with a coleopteran active Bt. Spear-Lep’s sister product, Spear-T, is applied at a higher rate, and without Bt, for activity against smaller soft-bodied pests via contact activity. Along with safety for humans, pollinators, and other beneficials, Spear is exempt from residues with a 4-hour REI and 0-day PHI.
Q. What crops are on the label?
A. Spear-Lep has a full label for lepidopteran larvae in most all cropping groups, including Almonds, Pistachios, Walnuts, Pome & Stone Fruits and vegetable crops.
Q. Are there any recommended methods to enhance the efficacy of the product?
A. Best performance depends on complete coverage; use a non-ionic surfactant and smaller droplet size.
DISCLAIMER: Please note that the entry is not a recommendation of the product for use. This article contains facts and opinions, and is intended to provide information so that you can learn about new technology that may be of use for your farm. All pesticides must be legally applied as per the pesticide label and local laws and regulations. Discussions with the operation's pest control advisor should occur to determine need and use.
Finally, I did not receive any financial compensation for this article, I simply think the technology is interesting.