Behavior and development of Tetranychus ludeni Zacher, 1913 (Acari: Tetranychidae) and physiological stress in genetically modified cotton expressing Cry1F and Cry1Ac proteins

Abstract

Genetically modified plants are one of the tactics used in integrated pest management - IPM. There is great concern about the impact of these plants on non-target organisms. On the other hand, there is little information in the literature on the effects of transgenics (Bacillus thuringiensis) Bt on populations of phytophagous mites, and the physiological responses that this attack promotes on plants. The objective of this work was to evaluate the biology of the T. ludeni mite in Bt cotton, expressing the Cry1F and Cry1Ac proteins. To evaluate the behavior of food and oviposition preference of the T. ludeni with Bt cotton and isohybrid. Verify if the physiological stress caused by T. ludeni’s attack is differentiated in Bt cotton. The mites were reared in Bt cotton and isohybrid, in a total of 40 replicates in the completely randomized design and the biological cycle was evaluated. The food preference and oviposition analysis were done with 10 replicates, with choice. The physiological stress was evaluated through chlorophyll fluorescence, under greenhouse conditions. The data of the T. ludeni biology were analyzed by Student's t-test, for food and oviposition preference the chi-square test was performed. Regression models were fitted for the fluorescence parameters. The model identity test was used to evaluate the differences between Bt and isohybrid treatments. Cry1F and Cry1Ac proteins have not affected the biology of T. ludeni. The photosynthetic parameters in Bt cotton plants were less influenced by T. ludeni infestation.

Mites (Acari) threaten ex situ conservation actions of Ipomoea cavalcantei D.F. Austin (Convolvulaceae), an endemic species from Carajás National Forest, Pará, Brazil

“…Tetranychus ludeni has been observed causing significant damage to Ipomoea batatas (L.) Lam. (Soares et al 2012;Castro et al 2019) and Gossypium hirsutum L. (Malvaceae) (Silva 2002;Moraes & Flechtmann 2008;Valadares et al 2021). In the multi-diverse Brazilian Amazon, T. ludeni has only been found on Tithonia diversifolia (Hemsl.)…”

Ipomoea (Convolvulaceae) plants as new hosts of Tetranychus ludeni (Acari: Tetranychidae)

“…The identification of this mite on these plants contributes to explain its permanence in the field, increasing its damage potential in cultivated plants (Soares et al, 2012). Ipomoea alba, I. cairica and I. indica are important as ornamental plants and also in the medicine and food, the latter for I. alba (JBRJ, 2020) (Mendonça et al, 2011;Soares et al, 2014;Valadares et al, 2021).…”