Biology of the black and green leaf folders of sweet potato [Philippines]
1981
Gapasin, D.P. | Rebadulla, L.Z. (Visayas State Coll. of Agriculture, Baybay, Leyte (Philippines). Dept. of Plant Protection)
The biology of the black leaf folder, Brachima sp., and the green leaf folder, Psana hipponalis Walker, considered important defoliators of sweet potato, were studied in the laboratory. The total developmental period of the black leaf folder (20 days) is shorter than the green leaf folder (24 days) and did not vary between sexes. Both species have 5 larval instars. A female laid an average of 44 and 90 eggs/day and the adults lived for 5 and 6 days for black and green leaf folders, respectively. Morphologically, the black leaf folder larva has prominent black and white markings on the thorax and abdomen while the green leaf folder larva is greenish yellow with dark brown head and prothoracic plate and found inside the folder leaf. The adults are about the same size but the black leaf folder moth is grayish black while the green leaf folder is yellowish brown with dark brown markings on its wings. Besides sweet potato, black leaf folder can complete development only on Ipomoea triloba and F. aquatica while the green leaf folder on Ipomoea purpurea, I. aquatica, I. pres-caprae; I. triloba and Mekania macrantha. Brachymeria sp. and another hymenopterous parasite attack green leaf folder while Macrocentrus sp. and an earwig species attack black leaf folder.
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