Category Archives: Trial Results

2011 Bt Research

Dr. Marcus Adair, Senior Field Research and Development Scientist for Valent Biosciences Corporation shares insight on current research issues.

Q: What are some of the key questions you are looking to answer?

Dr. Adair: From a company perspective, I think the one of the key questions involved our research with Bt and synthetic pyrethroids (SP). The objective was determining if our Bts in combination with one of the older SPs would result in synergistic activity. Would the combinations at low rates provide better activity than full rates of either component? This would have benefits economically for the grower as well as allow minimal rates of synthetic pyrethroids and minimal disruption to beneficial insects. Another question pertains to the development of resistance to key conventional insecticides. Despite knowledge gained in sound biological control or IPM practices in the past years, some chemicals are still being overused. The question we’re trying to answer is how quickly resistance may develop in key economic pests to these compounds.

Q: What are you learning about those key questions?

Dr. Adair: Data from 2010 trials are generally showing good results from the Bt + SP combination treatments against key pests. Results from resistance studies are still inconclusive at this point.

Q: What was the most striking element that came out of last year’s trials?

Dr. Adair: I would think that our success in demonstrating excellent insect control in experiments where Bts were rotated with the newer active ingredients.

Q: Are you testing any new formulations?

Dr. Adair: VBC is continuing research efforts in developing new and improved formulations of Bts. This is actually more of a research progress report than a question, although we are trying to answer the question of activity of these improved formulations/strains compared to existing products. Aggressive evaluation programs have been initiated in the last two years to determine comparative activity of these compounds.

Q: Earlier you mentioned resistance. Has resistance been reported? Is it a looming threat?

Dr. Adair: The use of Bts are an excellent option for “within cycle” rotation and tank-mixing to minimize resistance selection pressure. This practice will help in maintaining the current arsenal of newer insecticides (rynaxypyr, flubendiamide) and allow use of all the older products such as synthetic pyrethroids, spinosad and so on.

It is now reported that growers in Central Thailand and Central Phillippines are experiencing insecticide resistance to diamide chemistry in the diamondback moth. Resistance studies are showing high levels of resistance to flubendiamide in Central Thailand and rynaxypyr in Central Phillipines. This resistance development follows 2-4 years of using this class of chemistries in the marketplace.

Efficacy of XenTari* Biological Insecticide in Late-Season Application as Part of a Rotational Program to Control Lepidopteran Pests in Collard.

Insecticide chemical residue on crops is a major concern of both government agencies and consumers. XenTari* DF biological insecticide has no residue restrictions associated with its use, making it ideal for application at the end of the season and right before harvest. In this study XenTari* was applied at the end of a rotational program with Coragen*. This program provided excellent control of heavy infestations of cabbage looper and imported cabbage worms on collards.

Efficacy of XenTari* DF Biological Insecticide for Organic Control of Cabbage Looper and Imported Cabbage Worm Larvae on Collards

Organic growers have a limited number of products they can use for control of insect pests. In this study, the OMRI-listed biological insecticide XenTari* DF was tested for efficacy in control of imported cabbage worm and cabbage looper in collards. A XenTari* only program provided significant control of a heavy pest infestation compared to the untreated check. This study indicates that XenTari* can be an effective stand-alone insecticide for control of Lepidoptera pests

Efficacy of a XenTari* DF/ Coragen* Season-Long Program for Control of Beet Armyworm in Florida

XenTari* DF biological insecticide was partnered with Coragen* insecticide in a season-long program for control of armyworm pests in tomato. The rotation of these two soft insecticides provided better fruit protection and greater tomato yield, as measured by fruit weight, than a program of Coragen* alone. The XenTari*/Coragen* program also increased the profit per acre compared to the Coragen* only program.

Evaluation of Tank Mix Combinations of XenTari* Biological Insecticide and Bifenthrin Synthetic Pyrethroid Insecticide in Control of Diamondback Moth on Cabbage.

The Bacillus thuringiensis subsp. aizawai insectide XenTari* DF and the synthetic pyrethroid active ingredient bifenthrin were tank mixed and applied to cabbage for control of diamondback moth (Plutella xylostella) larvae. The tank mix combination of low label rates of XenTari* with bifenthrin provided better control than higher rates of either insecticide alone. Low to moderate rates of synthetic pyrethroids and Bt can provide good control with potential additional benefits such as beneficial insect conservation and reduced MRL concerns.

Efficacy of DiPel* DF Biological Insecticide for Organic Control of Diamondback Moth Larvae on Collards

Organic growers have a limited number of products they can use for control of insect pests. In this study, the OMRI-listed biological insecticide DiPel* DF was tested at two rates for efficacy in control of diamondback moth larvae in collards. A DiPel* only treatment program provided significant control of pest populations through the season. This study indicates that DiPel* can be an effective stand-alone insecticide for control of Lepidoptera pests.

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