Evaluation of two nematode strains (Steinernematidae: Heterorhabditidae) for the control of spittlebug (Hemiptera: Cercopidae) nymphs in sugarcane

The spittlebug or froghopper is an important pest of sugarcane that encompasses a complex of species in the genera Aeneolamia and Prosapia (Hemiptera: Cercopidae). Control of these insects is carried out with chemical insecticides; however, effective control is not always achieved. Also, entomopathogenic fungi, such as Metarhizium anisopliae, have been applied, and the use of entomopathogenic nematodes (EPN) has been proposed. In this study, we assessed the field virulence of two native strains, Steinernema sp. CP13ES (group IV, bicornutum-certophorum-riobrave) and Heterorhabditis indica CP13JA, collected from sugarcane fields of Constancia and La Gloria sugarcane mills in Veracruz, Mexico. Field trials were conducted in two areas of these sugarcane mills. Both strains were mixed with the adjuvant Break-Thru (R) and were sprayed in sugarcane plots infested with spittlebug nymphs. In the first trial, we tested the efficacy of the two EPN strains in conjunction with a dispersant agent to select the most appropriate strain. In the second trial, we evaluated Steinernema sp. strain considering 1-m(2) field plots. Results from trial 1 showed that both strains were significantly similar (P > 0.05) in their virulence: H. indica, recorded 73% mortality and Steinernema sp. 62%. Results from trial 2 demonstrated that the Steinernema strain was able to maintain a significantly lower (P = 0.25) spittlebug population for 4 days when compared to the control, whereas the nymph populations doubled during the same time period. These studies show the potential of the native EPN for field control of spittlebug nymphs in Mexico.