Confirmation on Status of Chaetocnema basalis (Coleoptera: Chrysomellidae) as A Vector of Stewart Wilt Disease

Abstract

Chaetocnema pulicaria and C. denticulata are recognized as vectors of Stewart wilt disease caused by Pantoea stewartii on maize. These insects have not been reported yet in Indonesia, but Stewart wilt disease has been reported in Java and Sumatera Islands. Genus Chaetocnema which presented in Indonesia is C.basalis. It is not cleared whether C. basalis is a vector for Stewart wilt disease like C. pulicaria and C. denticulata. This reseach was aimed to conduct the confirmation on status whether C. basalis have a role as vector of Stewart wilt disease on maize or not. C. basalis imago were collected from maize growing areas in Yogyakarta, and then starved for 24 h. Treatments were applied by placing imago of C. basalis on infected-P. stewartii plants for 72 h. Five insects were then transferred to each plot of healthy plant (1 plot consisted of 5 plants) for 72 h. For control, imago of C. basalis were put on healthy plants for 72 h and five insects were then transferred to other healthy plant (1 plot consisted of 5 plants) for 72 h. Each treatment was repeated three times. On the fifteenth days after transmission, PCR assays were carried out on leaf samples and isolates of bacteria. All sampled leaves analysis showed that there were no Stewart wilt diseases transmission based on PCR assay and bacterial isolates. This concluded that C. basalis is not a vector for Stewart wilt disease on maize.

Revision of the Oriental Chaetocnema species (Coleoptera, Chrysomelidae, Galerucinae, Alticini)

“…A recent research has also confirmed that 'C. basalis' (= C. nigrica) is a vector of Stewart Wilt disease in Indonesia (Widodo et al, 2017).…”

Status and Recent Developments of Pantoea stewartii subsp. stewartii Causes the Wilt Disease in Maize in Indonesia: A Review

“…More specifically, it stated that C. pulicaria is the only species important for the long-term survival of bacteria during the winter. In Indonesia, Widodo et al (2017) have even confirmed that insects of the same genus, namely C. basalis fed to maize, were infected with P. stewartii subsp. stewartii is not capable of transmitting the disease to healthy maize plants.…”

“…stewartii on corn in West Sumatra also used PCR. Widodo et al (2017) used PCR detection to detect P. stewartii subsp. stewartii in Java and Sumatra, as well as confirming the presence of C. basalis in Indonesia, is not a vector of pathogens.…”