Preliminary investigation on the morphological and biological characteristics of Haritalodes derogata

With the increasing damage caused by the cotton leaf roller, Haritalodes derogata, in some regions, this study preliminarily investigated the morphological and biological characteristics of this insect at different developmental stages to improve the accuracy of field identification, prediction, and forecasting. The results showed that the eggs of H. derogata were flat and oval-shaped, with a length of 0.74 mm and a width of 0.52 mm. The egg stage lasted for 3.21 days. The egg had a reticulated shell, and the hatching rate was 94.36%. The larvae with five instars were covered with sparse bristles, and produced silk to curl leaves, causing damage. The larval stage lasts for 24.52 days. Newly hatched larvae were yellowish-white in color, gradually changing to light green, dark green, gray green and peach pink as they grew and developed. The pupae were slender and spindle-shaped, initially transparent with a pale yellowish-green hue, gradually changing to reddish-brown and black-brown. The fourth abdominal spiracle was large, and there were 7-8 caudal hooks. The pupae measured 13.89 mm in length and 3.47 mm in width, with an initial pupal weight of 81.64 mg. The weight of pupa on the day before emergence only decreased by 1.69% compared to its initial weight. The pupal stage lasted for 9.74 days. Adult emergence mainly occured during the dark period from 23:00 to 05:00. The adult antennae were filamentous, and the bodies were light yellow. The leading edge of the middle cell of the forewing had "OR"-shaped brown spots. The weights of the adult and the pupal exuviae were 33.34 mg and 17.31 mg respectively, and the total weights of both combined were 37.90% less than those of the initial pupal weight. The adult body length was 12.67 mm, with a pre-oviposition period of 3.28 days and an oviposition period of 15.33 days. A single female could lay up to 761.37 eggs, and the adult lifespan was 22.03 days. H. derogata exhibited a high egg production and a high hatching rate, posing a potential risk of outbreak in Quanzhou, Fujian Province. Therefore, relevant departments should strengthen the forecasting and warning of this pest. This paper provides a detailed description of the morphological and biological characteristics of H. derogata at different instars. It provides a reference for rapid and accurate identification by grassroots pest forecasters and scientists, and provides basic information for field surveys, monitoring, and forecasting of this pest.