Identification and Control Methods for the Lily Pest Cotton Aphid

Its harm to plants is second only to the green peach aphid, and it also has many host species, mainly chrysanthemums, lilies, and others.

Morphological features: female aphids are winged or wingless, extremely small in size, initially pale yellow, later black. Legs and antennae are yellow-white. Male aphids are all wingless, 1/3 shorter than female aphids, and similar in color. Eggs are oval, yellow when first laid, turning black when hatching. Nymphs are gray-white at first, later turning yellow. When mature, those with wing buds on the thorax and back are winged mother aphids, while those without wing buds are wingless mother aphids.

Damage habits: the cotton aphid can produce 20 generations a year, overwintering as eggs on plant roots. In March of the following year, it reproduces by parthenogenesis and viviparity on the overwintering host, producing winged aphids that migrate to plants and cause damage. Damage is severe in July and August, until October, when they mate, lay eggs, and overwinter. Cotton aphids damage young branches, leaves, and flower buds, causing leaves to lose green color and curl up, and to become hard and brittle; in severe cases, the whole plant withers.

Control: eliminate overwintering insect sources, clear nearby weeds, and thoroughly clean the garden and field. During the aphid damage period, spray 40% dimethoate or omethoate at 1200 times dilution, or menazon emulsion at 150 times, or 2.5% derris extract at 1000-1500 times. Protect natural enemies, namely the seven-spot ladybird, hoverflies, and green lacewings, and others.