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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 #331675
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: First record of epizootics in the ocola skipper, Panoquina sp. (Lepidopera: Hesperiidae), caused by Isaria tenuipes in flooded rice fields of Central Brazil

Author
item MASCARIN, GABRIEL - Embrapa
item Dunlap, Christopher
item BARRIGOSSI, JOSE ALEXANDRE - Embrapa
item QUINTELA, ELIANE - Embrapa
item DE NORONHA, N - Embrapa

Submitted to: Journal of Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/24/2016
Publication Date: 2/15/2016
Publication URL: http://handle.nal.usda.gov/10113/5879006
Citation: Mascarin, G.M., Dunlap, C.A., Barrigossi, J.D., Quintela, E.D., De Noronha, N.C. 2016. First record of epizootics in the ocola skipper, Panoquina sp. (Lepidopera: Hesperiidae), caused by Isaria tenuipes in flooded rice fields of Central Brazil. Journal of Applied Microbiology. 122:1020-1028. doi: 10.1111/jam.13390.

Interpretive Summary: ARS researchers from Peoria, IL collaborated with Brazilian scientists from Embrapa to characterize a natural disease outbreak that greatly reduced the population of an insect crop pest. The insect was rice skippers, a caterpillar that damages rice plants through feeding on the leaves. The study discovered the disease was caused by natural insect killing fungus, known as Isaria tenuipes. The study shows under certain condition natural fungi can very effectively control insects pests. Understanding the environmental and ecological conditions that allowed the disease to progress will improve the use of microbial biological control agents in integrated pest management systems. This research benefits U.S. farmers and consumers that rely on crops impacted by insect pests.

Technical Abstract: Fungal entomopathogens serve an important ecological function by naturally regulating insect pest populations in agricultural crops worldwide. We report the first occurrence of an epizootic of the ascomycetous fungus Isaria tenuipes on rice skipper Panoquina sp. (Lepidoptera: Hesperiidae), a major pest affecting rice in Brazil. This fungus was found causing high infection levels (average 86.2±3.2%) mainly in the pupae of this pest during warm, humid growing conditions in flooded rice fields in the state of Goiás. Typically, mycosed pupal cadavers produced milky-white to pale yellow synnemata bearing an average total of 1.11±0.17 × 10**9 conidia per cadaver. This large number of conidia on the cadavers probably assures efficient horizontal transmission of the fungus within the host population. Based on phylogenetic analysis using beta-tubulin gene sequences, we confirmed that all 12 isolates obtained from mycosed pupae were identifiable as I. tenuipes. Our data expand our knowledge on the host and geographical ranges of this mycopathogen and underscore its epizootic potential to affect a serious lepidopteran pest on rice in Brazil.