Pyrilla perpusilla, Wlk., is one of the most destructive sugar-cane pests in the Punjab. It is widely distributed and, in addition to sugar-cane, it also feeds on wheat, barley, oats, maize, “chari” and a number of grasses.
Descriptions of the egg, nymphal and adult stages are given.
A female can lay 773 eggs in its life-time. The eggs are laid in clusters on the food-plants and are covered with whitish fluffy material. The egg stage occupies 7–12 days during April–October and 20–41 days during November–March. There are five nymphal instars. The nymphal stage occupies 24–65 days during April–September and 78–208 days during October–March.
Both adults and nymphs do damage. They prefer to feed on those varieties of sugar-cane which have broad, fleshy and succulent leaves and thick, soft stems. As a result of their feeding sucrose is reduced by as much as 34·2 per cent., while the glucose ratio may be trebled.
The pest is parasitised by the following insects:—Ooencyrtus papilionis, Ashm., Tetrastichus pyrillae, Craw., andLestrodryinus pyrillae, Kieff. (Hymenoptera); and Pyrilloxenos compactus, Pierce (Stylopidae). The following are predacious upon it: Brumus suturalis, F., Chilomenes sexmaculatus, F., Coccinella septempunctata, L., and C. undecimpunctata, L. (Col.), and Epipyrops sp. (Lep.). The incidence and duration of the life-cycles of these parasites and predators are given.
To control the pest the following measures are suggested:—(1) Destruction of the adults by hand nets during April; (2) destruction of the eggs by crushing during April; (3) destruction of the nymphs by a new hopperdozer during November–March; (4) dusting with nicotine dust or spraying with nicotine sulphate-fish oil soap mixture.