Identification and Control Methods of the Greenbug

Scientific name Schizaphis graminum (Rondani), order Homoptera, family Aphididae. Distributed throughout the country.

Hosts: @#@245@#@, barley, oats, sorghum, rice, foxtail grass, sedge and other grasses.

Damage characteristics: The greenbug often feeds on sap on both the front and back of wheat leaves or inside and outside the basal leaf sheaths, causing wheat seedlings to turn yellow and wither or to lie flat and be unable to joint, and severely affected wheat plants cannot head normally, directly affecting yield; in addition, it can also transmit wheat yellow dwarf virus.

Morphological characteristics: The wingless parthenogenetic female is 2.0 mm long, oval, light green, with a dark green dorsal midline and light green cornicles with black tips. The mesothoracic ventral fork has a short stalk. The frontal tubercles are higher than the median frontal tubercle. The antennae have 6 segments, with the total length exceeding half the body length; the rostrum extends beyond the middle coxae, and its terminal segment is thick and short, 1.6 times as long as its basal width. The cornicles are long and cylindrical; the cauda is long and conical, 1.5 times as long as its basal width, with 5-6 long hairs. The winged parthenogenetic female is 1.8 mm long, long oval. When alive it is green with a dark green dorsal midline. The head and thorax are black, and the abdomen is light in color. The antennae are black with 6 segments in total, and the total length exceeds half the body length. The third antennal segment has 4-10 small circular secondary rhinaria arranged in a row. The media of the forewing is forked.

Life habits: The life habits of the greenbug are similar to those of the English grain aphid, with 20-30 generations per year, and the specific number of generations varies by region. In winter-spring wheat mixed planting areas and early-sown

Population dynamics in winter wheat fields: After the autumn seedlings emerge, they begin to migrate into wheat fields and reproduce. A small peak occurs from the 3-leaf stage to the tillering stage, and in early November they overwinter as eggs on stubble in winter wheat fields. In early to mid-March of the following year, the overwintering eggs hatch, and after reproducing for several generations on winter wheat, some continue to reproduce as wingless viviparous females, while others produce winged viviparous females that reproduce and spread in winter wheat fields. In mid-April some migrate to spring wheat, and in early to mid-May they reproduce in large numbers, creating a peak damage period and potentially causing yellow dwarf disease epidemics. The development rate of the greenbug is positively correlated with temperature from 10-30°C; the survival rate is low below 7°C, viviparous reproduction is fast at 22°C, growth and development are fastest at 30°C, and it dies rapidly at 42°C. Under suitable conditions, this aphid has strong reproductive capacity and a short developmental period. During the jointing and booting stages of wheat, the population density rises rapidly, often reaching more than 10,000 aphids per 100 plants within 15-20 days.

Control methods are the same as for the English grain aphid.