Effect of wavelength on development and demographic parameters of Scolothrips longicornis fed on two-spotted spider mites

Authors: PAKYARI, HAJAR - Islamic Azad University; Reddy, Gadi V.P.

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2022
Publication Date: 7/8/2022
Citation: Pakyari, H., Reddy, G.V. 2022. Effect of wavelength on development and demographic parameters of Scolothrips longicornis fed on two-spotted spider mites. Crop Protection. https://doi.org/10.1016/j.cropro.2022.106052.
DOI: https://doi.org/10.1016/j.cropro.2022.106052

Interpretive Summary: The two-spotted spider mite has a worldwide distribution and can feed on more than 900 plant species, including various annual and perennial crops. Control of two-spotted spider mite with synthetic pesticides is challenging because of its short development time, high fecundity, habit of feeding on the lower leaf surface (reducing efficacy of acaricide applications), and rapid development of acaricide resistance. Biocontrol programs play an important role in population management of spider mites. Entomophagous control agents include a wide range of taxa such as acarophagous ladybird beetles, predatory anthocorids, predatory mites and predatory thrips. Most of the above-mentioned predators feed on a variety of soft bodied insects and several groups of mites, but all species of thrips appear to be specialized predators of spider mites. Previous research has not evaluated the influence of light wavelength on the life table parameters of thrips. To optimize mass rearing of thrips, we determined the influence of light wavelength (white, blue, green, yellow and red) on life tables of thrips. The present research demonstrates that white light conditions have a positive influence on thrips with shorter development time and improved reproductive performance. The better performance under white light conditions is most possibly an outcome of its similarity to sunlight. There is a necessary for future research on the influence of various light aspects on physiology and molecular causes of these results.

Technical Abstract: The wavelength of light can affect reproduction and development of arthropods. In the present study I examined the reproduction and development of predatory thrips Scolothrips longicornis Priesner (Thysanoptera: Thripidae) fed on Tetranychus urticae Koch (Trombidiformes: Tetranychidae) eggs, under five wavelengths: white (all wavelengths), blue (475 nm), green (580 nm), yellow (620 nm) and red (675 nm), at 25±0.5ºC, 16L: 8D and 60±10% rh. Light wavelength did not significantly influence female and male preadult duration. Male adult duration and male total longevity were not influenced by the light wavelength treatment. The mean minimum and maximum female total longevity were recorded under red light conditions, (28.05±0.81d), and white light conditions, (33.5±1.08d) treatments, respectively. White and green light yielded the longest duration of oviposition periods. Females held under white light demonstrated a higher reproductive performance than those under other wavelengths. This information will be beneficial in mass production of S. longicornis for biocontrol programs involving T. urticae.