Role of volatiles emitted by host and non-host plants in the foraging behaviour of Dentichasmias busseolae, a pupal parasitoid of the spotted stemborer Chilo partellus

Publication Type

Journal Article

Journal Name

Plant Disease

Publication Date

9-1-2016

Abstract

African nightshades (Solanum spp.) are important leafy vegetables in many parts of eastern, western, central, and southern Africa (Keding et al. 2007). In Kenya, sustainable production of African nightshades faces a twin challenge from both above- and belowground pests. Root-knot nematodes (RKN; Meloidogyne spp.) are belowground pests capable of parasitizing many hosts including African nightshades, leading to severe yield loss and sometimes total crop failure. A survey was carried out in Kenya between May and July 2015 to determine the presence and incidences of RKN infecting the African nightshade Solanum scabrum. In the field, this nightshade exhibited the following symptoms: leaf yellowing, leaf drop, and stunted growth. Symptomatic African nightshade plants isolated from Yatta, Machakos County showed very large galls in comparison with those commonly associated with Meloidogyne incognita and M. javanica infected African nightshade plants. Population densities of infective second stage juveniles in the soil ranged from 100 to 750 individuals per 100 cm3 soil. To characterize the Meloidogyne species, single adult females (n = 20) were picked from galled nightshade roots for morphological analysis. Female perineal patterns were similar to those in the first description of M. enterolobii (Yang and Eisenback 1983); however, some samples deviated from the original description by showing a moderately high to high dorsal arch. Therefore, DNA was extracted separately from 10 single females and PCR was used to amplify a 420-bp fragment of cytochrome oxidase I (COI) of the mitochondria (Derycke et al. 2010). The PCR products (represented by accession no. KT936633) were sequenced and aligned with sequences in GenBank. BLAST analysis resulted in 100% identity to the sequence of an M. enterolobii isolate from China (GenBank Accession No. JX683714). Using DNA of the same females, species identification was also confirmed using PCR species-specific SCAR primer set MK7-F/MK7-R (Tigano et al. 2010). No amplification was produced with the specific primers for other tropical species (M. javanica, M. incognita, and M. arenaria). The same results were obtained from females cultured on S. scabrum in the greenhouse. M. enterolobii is considered to be a highly pathogenic plant-parasitic nematode species because it is able to reproduce on varieties of tomato, tobacco, watermelon, and pepper that are resistant to other RKN species. In addition, the pathogenicity and reproductive potential of M. enterolobii is higher when compared with other tropical RKN such as M. javanica, M. incognita, and M. arenaria (Kiewnick et al. 2009). To our knowledge, this is the first report of M. enterolobii in Kenya.

Link to Full Text

Share

COinS