Subterranean acoustic activity pattersn of Vitacea polistiformis (Lepidoptera: Sesiidae) in relation to abiotic and biotic factors

Authors: INYANG, E - Florida A & M University; HIX, R - Florida A & M University; COLOVA, V - Florida A & M University; ROHDE, B - University Of Florida; DOSUNMU, O - University Of Florida; Mankin, Richard

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2019
Publication Date: 8/23/2019
Citation: Inyang, E., Hix, R.L., Colova, V., Rohde, B., Dosunmu, O., Mankin, R.W. 2019. Subterranean acoustic activity pattersn of Vitacea polistiformis (Lepidoptera: Sesiidae) in relation to abiotic and biotic factors. Insects. 10(9):267. https://doi.org/10.3390/insects10090267.
DOI: https://doi.org/10.3390/insects10090267

Interpretive Summary: The grape root borer is a major pest within southeastern US vineyards. The larvae feed underground and are difficult to detect except by acoustic methods. Scientists at Florida A&M University, University of Florida, and the USDA, Agricultural Research Service, Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, Florida, conducted a long term study to monitor larval activity in an experimental vineyard. Acoustic monitors showed that larval activity was greater in the fall than the winter or spring, and greater in the evening than the afternoon. The likelihood of infestation was estimated for each recording site based on the rates of insect sounds detected. Sites with high likelihood of infestation were confined within small sections of the vineyard, while most of the recording sites were rated at low infestation likelihood. This suggests that acoustic monitoring could be used to localize infestations within a vineyard thus facilitating reductions in the area subject to treatment for the grape root borer.

Technical Abstract: Grape root borer (GRB), Vitacea polistiformis (Lepidoptera: Sesiidae), is a major pest in Florida vineyards. It is difficult to optimize timing and targeting of management treatments against GRB because the decreases in grape yield and vine health caused by GRB root damage do not appear until the following season. Consequently, we considered whether monitoring of seasonal and diel patterns of GRB subterranean acoustic activity across a vineyard could inform efforts to time and target control treatments. After pheromone trapping confirmed the presence of GRB in a Vitis rotundifolia vineyard in July, 2014, a 269-d study was begun in early fall to record sounds from root systems at 31 spatially distributed sites at different times of day. Characteristic spectral and temporal patterns in the recorded trains (bursts) of GRB sound impulses enabled them to be discriminated from background noise. The GRB infestation likelihood at each site was estimated from previous studies relating insect presence to sound burst rate. Sites with high burst rates and high infestation likelihoods were confined within a small section of the vineyard, and 39% of recording sites were rated at low infestation likelihood. This suggests that acoustic monitoring could facilitate reductions in GRB treatment coverage. Sound burst rates were greatest in fall, suggesting that springtime reductions in GRB activity may occur just before larvae pupate and adults emerge. Monitoring of springtime activity thus may enable improved predictions about the timing of neonate emergence. Neonates, the stage most vulnerable to pesticides, are preferred targets for treatment.