Biology and management of pest Diabrotica species in South America

Authors: CABRERA WALSH, GUILLERMO - Fuedei; AVILA, CREBIO - Embrapa; CABRERA, NORA - National University Of La Plata; NAVA, DORI - Embrapa; PINTO, ALEXANDRE DE - Moura Lacerda University Center; Weber, Donald

Submitted to: Insects
Publication Type: Review Article
Publication Acceptance Date: 7/3/2020
Publication Date: 7/8/2020
Citation: Cabrera Walsh, G., Avila, C.J., Cabrera, N., Nava, D.E., Pinto, A.S., Weber, D.C. 2020. Biology and management of pest Diabrotica species in South America. Insects. https://doi.org/10.3390/insects11070421.
DOI: https://doi.org/10.3390/insects11070421

Interpretive Summary: Leaf beetles in the genus Diabrotica are very diverse with hundreds of recognized species in South America. Only three species are agricultural pests there, Diabrotica speciosa, Diabrotica balteata, and Diabrotica viridula. In general they are pests as adults by consuming the foliage of many crops and ornamentals, particularly beans, cucurbits, potato, and corn, and the larvae are pests on corn, eating the roots as do related corn rootworms in North America. Diabrotica balteata ranges into the southern US and is a pest of peanuts, cucurbits, corn, and sweet potatoes. The other two species are potential invasive pests in the US. This review summarizes the knowledge about life history and management of the three pest species in South America, including chemical, plant resistance including transgenic crops, biological, microbial, cultural, and behavioral controls current and future. The review should be of interest to pest management practitioners and researchers in the Americas.

Technical Abstract: The genus Diabrotica has 354 recognized species, the majority of them neotropical. However, only three species of neotropical Diabrotica are considered agricultural pests, D. speciosa (Germar), D. balteata LeConte, and D. viridula (F.). D. speciosa and D. balteata are polyphagous both as adults and during the larval stage. D. viridula is stenophagous during the larval stage, feeding essentially on maize roots, and polyphagous as adults. Adults of D. speciosa and D. balteata are considered damaging on many crops and ornamentals, particularly on beans, cucurbits, potato, and maize. The larvae of the three species are pests on maize, D. speciosa larvae are also considered pests of potatoes and peanuts, while D. balteata larvae are also pests of beans. Management options are generally limited to insecticide applications (including in-furrow applications), and GM maize expressing Bacillus thuringiensis (Bt) Cry3Bb1. Experimental management of adults has been attempted with biological control using entomopathogens and cucurbitacin-based toxic baits. Two species of adult parasitoids have also been studied and tested in the laboratory, the tachinid Celatoria bosqi Blanchard, and the braconid Centistes gasseni Shaw. Neither of them have been observed to exert much control on the pest Diabrotica populations, or to have much potential at this stage for inundative biocontrol plans, given their low reproductive rate, comparatively long development, and dependence on laboratory-reared adults. All of the South American pest Diabrotica lack a winter/dry season egg diapause, having only a facultative reproductive diapause in winter, with several, latitude-mediated generations per year. This hinders the use of crop rotation as a management tool, although early planting can help in the temperate regions of the distribution of D. speciosa. To date, farmers can only count on insecticide treatments for adults, soil insecticides for larvae, and GM crops to control pest Diabrotica. However, other techniques that show promise must continue to be explored, such as the use of toxic baits with semiochemical attractants to eliminate adults and for monitoring purposes, plant resistance, and biological control using Heterorhabditis nematodes against larvae.