Beneficial insects and PROCLAIM® Opti
Beneficial insects play an important role in horticulture; get the balance right and they can reduce or even eliminate the need for insecticides. The equilibrium between the pest and beneficial is a fine line; if you are going to conserve and/or release beneficial insects, you are going to have to create a habitat to support them and, where possible, utilise ‘softer’ Integrated Pest Management (IPM) compatible insecticides. When a new insecticide hits the Australian market, one of the first questions asked is what the impact is on beneficial insects.
Syngenta is able to utilise an extensive global database to answer this question, however, the most valuable insights are generated here in Australia. For example, when the formulation of PROCLAIM® was replaced with the recent PROCLAIM® Opti formulation, the Biological Research Company was engaged to evaluate what impact the new formulation had on a range of beneficial insects. Although the loading of the active ingredient in PROCLAIM® Opti was identical to PROCLAIM® (44 g/L emamectin), some of the other ingredients within the formulation changed, which altered the impact on some of the beneficial insects screened. This demonstrates that while products can appear to be the same on the label, differences in non-active ingredients can potentially have unexpected impacts.
Figure 1. Results from Biological Research Company study using full label-rate product.
Figure 1 shows that PROCLAIM® Opti has minimal impacts on generalist predators ladybirds (L) and pirate bugs (O) and is slightly harmful to green lacewings (G). PROCLAIM® Opti was rated as ‘harmful’ on a range of parasitoids including Aphidius colemani (aphid parasitoid), Diadegma semiclausum (diamondback moth parasitoid) and Eretmocerus hayati (whitefly parasitoid). This indicates that should these parasitoids be present when the crop is sprayed, they are likely to be impacted. However, this impact is very short-lived. PROCLAIM® Opti has translaminar activity, providing rapid absorption into the plant, with residual degradation by sunlight (half-life is 3.5 hours).
“This means any of these parasitoids migrating into the paddock in the days after the application would likely survive” explained Syngenta Technical Services Lead, Dr Shaun Hood. “Remember though, they are only going to settle and become established if their host is present.”
Every year at selected locations around Australia, Syngenta showcases its pipeline horticulture products at GrowMore Experience Sites. This year’s site was at Bowen in north Queensland, where a commercial crop of tomatoes and rockmelons were grown, using Syngenta’s new products in the spray program.
“The highlight is always the large untreated plots. It’s here where we get to watch the insects move in and become established with a range of beneficial insects responding as best they can to manage the pest population. Unfortunately, the beneficial insects invariably can’t keep up and the produce from those plots were unmarketable” advised Shaun.
‘Bug dorms’ were set up to demonstrate what impact the Syngenta insecticides had on a range of beneficial insects. Three representative predators were selected as they are highly mobile and their activity is relatively easy to observe: ladybirds (Harmonia conformis), green lacewings (Mallada signatus) and pirate bug (Orius tantillus). PROCLAIM® Opti was found to perform as well ‘in the field’ as it did in the lab.
“Effective and consistent monitoring of the crop is critical. Know the pest thresholds for your crop and trust the process, which may mean you hold off spraying until you reach that threshold” said Shaun. “Finally, understand the chemistry you’re using; its impact on beneficials, its resistance restraints, and how it will fit into your overall program. It really is a science, and using the best advice is essential in helping to get that right.