Spray-dried microencapsulated Bacillus thuringiensis formulations for the control of Epilachna varivestis Mulsant

Citation
P. Tamez-guerra et al., Spray-dried microencapsulated Bacillus thuringiensis formulations for the control of Epilachna varivestis Mulsant, SW ENTOMOL, 24(1), 1999, pp. 37-48
Citations number
23
Categorie Soggetti
Entomology/Pest Control
Journal title
SOUTHWESTERN ENTOMOLOGIST
ISSN journal
01471724 → ACNP
Volume
24
Issue
1
Year of publication
1999
Pages
37 - 48
Database
ISI
SICI code
0147-1724(199903)24:1<37:SMBTFF>2.0.ZU;2-4
Abstract
A new sprayable microgranule formulation of Bacillus thuringiensis subsp. k umomatoensis (strain C-9) was evaluated for the control of the Mexican bean beetle Epilachna varivestis Mulsant. Strain C-9 was isolated from dead E. varivestis in a Phaseolus vulgaris L. field in Durango, Mexico. A spore and crystal complex of the C-9 strain were active against E. varivestis larvae in bioassays using treated bean plants (LC50 of 642 mu g/ml), and against Trichoplusia ni (Hubner) larvae using artificial diets (LC50 of 219 mu g/ml ). The sprayable powder (microgranule formulation), consisting of cornstarc h (CS), nixtamalized corn flour (NCF), vegetable oil, powdered sugar, 2-pro panol, malachite green, and formaldehyde, was prepared using a spray-dry pr ocess. Shelf life of formulated B. thuringiensis maintained over 90% of its original activity after 24 months of storage. A field test demonstrated th at treatments of formulated B. thuringiensis controlled E. varivestis signi ficantly better than treatments with unformulated B. thuringiensis. This st udy demonstrated that B. thuringiensis can potentially be formulated by spr ay drying, based on ingredients, which would help to improve its activity a s a biopesticide under field conditions.