LiriomyzaLeafminer (Diptera: Agromyzidae) Parasitoid Complex in Different Agroecological Zones, Seasons, and Host Plants in Kenya

Abstract

Liriomyza leafminers (Diptera: Agromyzidae) are severe pests of vegetables and ornamentals worldwide. Previous studies revealed low leafminer parasitism across different agroecological zones in Kenya. The present paper reports on the composition of leafminer parasitoids at different elevations, in different seasons, and on different host crops. Surveys were conducted monthly from January to November 2012, and nine parasitoid species were recovered. Total mean parasitism in the study sites was 31.23 ± 1.03% from a total of 20 different vegetable Liriomyza-infested crops belonging to seven families. Diglyphus isaea (Walker) (Hymenoptera: Eulophidae), Phaedrotoma scabriventris, a newly released parasitoid, and Opius dissitus Muesebeck (Hymenoptera: Braconidae) were the most abundant at all elevations, accounting for 67.3, 18.6, and 9.2% of total parasitoids, respectively. Elevation, season, and host crop significantly affected the parasitoid species present and their abundance. Diglyphus isaea was more abundant at the high- and mid-elevations at all seasons compared with the low-elevation, whereas the lower-elevation favored higher abundance of P. scabriventris and O. dissitus during the long rainy season compared with the high- and mid-elevations at all seasons. Of all the host crops surveyed, parasitoids were more abundant on tomato, local kidney bean, snow pea and French bean than other crops. The total parasitism rate observed in this study suggests a considerable improvement in leafminer parasitism compared with previous surveys in Kenya. The implications of these findings for leafminer management in vegetable and ornamental production in Kenya are discussed.

Parasitoid Abundance and Community Composition in Desert Vineyards and Their Adjacent Natural Habitats

“…Parasitoid species composition was significantly affected by the sampling month, as was demonstrated in previous studies [48,59]. In addition, parasitoid composition significantly differed between the natural and the crop habitats.…”

Life history and biocontrol potential of the first female-producing parthenogenetic species of Diglyphus (Hymenoptera: Eulophidae) against agromyzid leafminers

“…Agromyzid leafminers are subject to parasitoids, particularly in their areas of origin, which may regulate leafminers populations in pesticide-free areas 6 , 9 – 11 . Noyes 10 listed more than 300 species of agromyzid parasitoids and over 80 species that attack Liriomyza species.…”

Potential for biological control of the vegetable leafminer, Liriomyza sativae (Diptera: Agromyzidae), in Australia with parasitoid wasps

“…in Kenyan crops by indigenous parasitoids, including H. varicornis, D. isaea and O. dissitus, was low (5%), although these data were obtained in indiscriminately sprayed commercial crops (Foba et al 2015). In subsequent surveys of crops where use of broad-spectrum insecticides was reduced, overall parasitism was 31% (Foba et al 2016). D. isaea was the dominant parasitoid at all elevations, while O. scabriventris had already established widely and had become the second most abundant parasitoid in the mid-and low-elevation fields (Foba et al 2016).…”

“…In subsequent surveys of crops where use of broad‐spectrum insecticides was reduced, overall parasitism was 31% (Foba et al . ). D. isaea was the dominant parasitoid at all elevations, while O. scabriventris had already established widely and had become the second most abundant parasitoid in the mid‐ and low‐elevation fields (Foba et al .…”

“…In subsequent surveys of crops where use of broad-spectrum insecticides was reduced, overall parasitism was 31% (Foba et al 2016). D. isaea was the dominant parasitoid at all elevations, while O. scabriventris had already established widely and had become the second most abundant parasitoid in the mid-and low-elevation fields (Foba et al 2016). The value of this classical biological control program remains to be assessed, but success will undoubtedly rely on farmers reducing broad-spectrum insecticide applications, which will also assist indigenous parasitoids in controlling L. huidobrensis.…”