Document Type : Agricultural Entomology
Authors
1 Plant Protection Research Department, Golestan Agricultural and Natural Resources Research Center, Agricultural Research, Education and Extension Organization, Gorgan, Iran.
2 Expert, Plant Protection Research Department, Golestan Agricultural and Natural Resources Research Center, Agricultural Research, Education and Extension Organization, Gorgan, Iran.
3 Expert, Plant Protection Research Department, Golestan Agricultural and Natural Resources Research Center, Agricultural Research, Education and Extension Organization, Gorgan, Iran
Abstract
Strawberry, Fragaria ananassa Duch. which belongs to the Rosaceae family is one of the most important micro-fruits of temperate regions that has been considered as one of the most important and commercial products in the recent decades. Golestan province is the third largest strawberry producer in Iran after Kurdistan and Mazandaran Provinces (Ahmadi et al., 2018). Spodoptera littoralis (Boisduval, 1833) is a highly polyphagous pest that attacks to a wide range of crops (Lanzoni et al., 2012). The eggs are whitish-yellow in color, spherical, somewhat flattened, with 0.6 mm diameter, surrounded by hair scales. The newly hatched larvae are 2 to 3 mm long with white bodies and black heads and are very difficult to detect visually. The larvae are hairless, cylindrical, and variable in color from blackish-gray to dark green, becoming reddish-brown or whitish-yellow. They have dark and light longitudinal bands on lateral sides; and with two dark semilunar spots on each segment (except for the prothorax) dorso-laterally. This pest has 5-6 larval instars, and length of full grown larvae is 40-45 mm. The pupae are cylindrical, 14-20 5 mm, and the last segment ends in two strong straight hooks. Firstly in green with reddish color on the abdomen, turning dark reddish-brown within few hours. The adult moth with length of 15-20 mm, and wingspan of 30-38 mm. It has a gray-brown body, with gray to reddish brown forewing that has paler lines along the veins, and grayish white hind wing, iridescent with gray margins (Pinhey, 1975).
Based on the available literature, the larvae of
S. littoralis are newly observed in Golestan Province on strawberry (Fig. 1). In the early stages of damage, the young larvae feed on small areas on the underside of the leaf. Older larvae make large holes in the leaves or eat them completely, or damage young branches, young buds and bare parts of the stems, severely. In the Khan Bebin fields where strawberry bushes left in the ground to produce stolons for reproduction, the larvae started to feed on the leaves from the early September, and with increasing the larval age, their feeding intensified and eventually caused destroying the central meristem of the plant. Egyptian cotton leaf worm with its high ability of reproduction, and feeding, can be considered as a serious and very important pest in Golestan province, due to the climatic conditions of the region.
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