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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Crop Bioprotection Research » Research » Publications at this Location » Publication #347754

Research Project: Development of Production and Formulation Technologies for Microbial Biopesticides in Conjunction with the Development of Attractants and Repellents for Invasive Insect Pests

Location: Crop Bioprotection Research

Title: Comparing formulations for a mixed-microbial biopesticide with Bacillus thuringiensis var. kurstaki and Beauveria bassiana blastospores

item SAYED, ATEF - Agricultural Research Center Of Egypt
item Behle, Robert

Submitted to: Archives of Phytopathology and Plant Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/17/2017
Publication Date: 9/24/2017
Citation: Sayed, A.M., Behle, R.W. 2017. Comparing formulations for a mixed-microbial biopesticide with Bacillus thuringiensis var. kurstaki and Beauveria bassiana blastospores. Archives of Phytopathology and Plant Protection. 50(15-16):745-760. doi:

Interpretive Summary: Biopesticides that use microbial agents as the active ingredient require special formulations to protect the microbes during storage, mixing, and application. Formulations made with natural ingredients are generally preferred by consumers. This research demonstrated that a several nature ingredients varied in their ability to improve mixing characteristics and residual insecticidal activity when used to formulate an experimental biological insecticide made with two microbes, the bacteria Bacillus thuringiensis and the fungus Beauveria bassiana. This knowledge is important for proper development of effective biopesticide products that will reduce environmental contamination and health hazards by successfully replacing toxic chemical pesticides for pest control.

Technical Abstract: Developing a dual agent biopesticide formulation made with blastospores of Beauveria bassiana (Balsamo) Vuillemin strain GHA (Bb) at the ratio of 1:1 mixed with traditional fermentation production of Bacillus thuringiensis kurstaki (Btk) spores and crystals were studied. Twelve potential formulation ingredients were screened for their impact on insecticidal activity, microbe viability, UV protection and product suspensibility of a spray dried Bt/Bb (1:1) mixture applications to cabbage plants against cabbage looper, Trichoplusia ni. Based on the results, Spray-dried mixtures of Bt/Bb made with biochar, chitosan and skim milk powder formulations gave the greatest efficacy and higher solar stability when exposed to simulated sunlight. They therefore can be used as a formulation that combines Bt with Bb in one product. However, the formulation made with aitkin component had significantly more colony forming units (CFUs) of Bt, whereas, formulations made with albumin, sodium carbonate and pharmamedia had more Bb CFUs than other formulations. Albumin, pharmamedia, skim milk powder and biochar had significantly better suspension in water (less settling) than others. These results support the concept of formulating the two biocontrol agents, B. thuringiensis and B. bassiana blastospores for greater efficacy, more viability and longer field persistence as an environmentally friendly sustainable pest control tool.