Sharpshooters, Leafhoppers, Cicadellidae (Insecta: Hemiptera: Auchenorrhyncha: Cicadellidae)

Sharpshooter is a term commonly used to describe a group of leafhoppers in the family Cicadellidae. There have been several explanations for the use of this term. Riley and Howard (1893) first used 'sharpshooter' to describe the feeding damage of the glassy-winged sharpshooter, Homalodisca coagulata (Say), on cotton. This damage was caused by the piercing-sucking mouthparts of H. coagulata that appeared to be caused by a 'minute bullet.' They also reported 'rapid and forcible ejection of minute drops of fluid' as another explanation for the use of this term. The term sharpshooter is also attributed to the hiding behavior of these insects when alarmed. Disturbed sharpshooters will slip quickly behind branches and stems to avoid predators, an action not unlike the behavior of army sharpshooter riflemen who would hide behind the trunks of trees to avoid detection by the opposition as they passed by their position. This document is EENY-334 , one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: October 2004. EENY-334/IN611: Sharpshooters, Leafhoppers, Cicadellidae (Insecta: Hemiptera: Auchenorrhyncha: Cicadellidae) (ufl.edu)

Codon Usage Bias in Two Hemipteran Insect Species: Bemisia tabaci and Homalodisca coagulata

Codon bias is the nonuniform use of synonymous codons which encode the same amino acid. Some codons are more frequently used than others in several organisms, particularly in the highly expressed genes. The spectacular diversity of insects makes them a suitable candidate for analyzing the codon usage bias. Recent expansion in genome sequencing of different insect species provides an opportunity for studying the codon usage bias. Several works on patterns of codon usage bias were done on Drosophila and other related species but only few works were found in Hemiptera order. We analyzed codon usage in two Hemipteran insect species namely Bemisia tabaci and Homalodisca coagulata. Most frequent codons end with A or C at the 3rd codon position. The ENC (a measure of codon bias) value ranges from 43 to 60 (52.80) in B. tabaci but from 49 to 60 (56.69) in H. coagulata. In both insect species, a significant positive correlation was observed between A and A3%, C and C3%, and GC and GC3%, respectively. Our findings suggest that codon usage bias in two Hemipteran insect species is not remarkable and that mutation pressure causes the codon usage pattern in two Hemipteran insect species.

Evaluation and Molecular Characterization of Beauveria bassiana for the Control of the Glassy-winged Sharpshooter (Homoptera: Cicadellidae) in California

The glassy-winged sharpshooter, Homalodisca coagulata (Say), is an important pest on grapes, citrus, almonds and other commercial crops in California as it is a vector of Xylella fastidiosa Wells, a bacterium that causes Pierce's disease in grapes, citrus variegated chlorosis, almond leaf scorch and other plant diseases. Various entomopathogenic fungi isolated from natural infections of H. coagulata, its habitats and other insect hosts were evaluated against this insect vector. Based on these studies, 3 isolates of the hyphomycetous fungus, Beauveria bassiana (Balsamo) Vuillemin, were selected for further evaluation. Two of these were California isolates, one each from the three-cornered alfalfa hopper, Spissistilus festinus (Say), and soil from H. coagulata habitat, and the third was a Texas isolate from natural infections of H. coagulata. All three were similar in their virulence to H. coagulata under laboratory conditions. The genetic relatedness of the B. bassiana isolates also was compared using single sequence repeat (SSR) markers which showed genetic diversity of this species based on the source of the isolate. Some isolates were 4× more infectious than others demonstrating that virulence of B. bassiana is not necessarily associated with their genetic relatedness.

Host plant testing of the spittle bug carystoterpa fingens by stylet penetration behaviour

Carystoterpa fingens (Walker) is an endemic xylem feeder It was chosen as a model insect for the glassy winged sharp shooter (Homalodisca coagulata (Say)) The electrical penetration graph (EPG) technique was used to measure realtime stylet penetration and feeding behaviour of 48 adult C fingens on four plant types hebe (Hebe pubescens) rengarenga lily (Arthropodium cirratum) wild iris (Dietes bicolor) and cabbage (Brassica oleracea) over 12 days EPG waveforms were recorded for 12 hours and the duration of the main penetration events (pathway ingestion and nonprobing phases) of the insects were analysed to compare host preferences There were no significant differences in the duration of ingestion indicating that all the plants were potential hosts for C fingens Insects on hebe showed the shortest nonprobing time suggesting that hebe was the most preferred host as expected from observations in the wild