Wheat larvae are world-wide pests and are widely distributed in major wheat-growing countries in Asia, Europe and the Americas. The domestic wheat larvae are also widely distributed in the main wheat producing areas of the country. There are two main types of wheat larvae in China, namely, red larvae and yellow larvae. Wheat red-sucking worms mainly occur on the banks of the river in the plains, while the yellow-sucking worms mainly occur in plateaus and high mountains.

Morphological characteristics of winter wheat

The adult female larvae of the red-sucking worm are 2 to 2.5 mm long and have a wingspan of about 5 mm. The body is orange-red. The front wings are transparent, with 4 well-developed wings and the hind wings degenerate into balance sticks. The antennae are slender, 14 knots, and the males contract in the middle of each section to make the knots goose-shaped, and most of them have a long ring of hair. The female antennae are beaded and have a short ring of hair. The male body is about 2mm long.

Egg length 0.09mm, oblong, light red. The larvae have a body length of 3 to 3.5 mm, an elliptical shape, an orange-yellow shape, a small head, no foot, and a scorpion shape. There is a "Y-shaped" sword bone on the ventral surface of the front chest, and the front end is bifurcated and the depression is deep.蛹 2mm long, naked, orange-brown, with 2 short white hairs and 1 long snorkel in front of the head.

Wheat yellow sucking worm, the female body is about 2mm long, and the body is bright yellow. The egg is 0.29mm long and has a banana shape. The larvae are 2 to 2.5 mm long, yellow-green or ginger-yellow, with a smooth surface. There are sword bones on the front and back of the chest, and the front end of the sword bone is curved and split, and there are 2 protrusions at the end of the abdomen. Fresh yellow, with 1 pair of longer hair at the head.

Winter wheat sucking insect damage symptoms

The larvae lurk in the hulls to suck the granules of the grain being grouted, causing glutinous grains and empty shells. Wheat larvae are devastating pests that use larvae as flower stalks, seed stalks, or wheat granules.

Winter wheat sucking insect damage characteristics

Both sucking worms occur one generation a year. In the case of unhealthy environmental larvae, they have many years of dormancy, so there are also many generations. The mature larvae are rounded in the soil for wintering and summering. In the middle and upper reaches of the Huanghuai River Basin in March, the wintering larvae broke into the soil surface, and in the middle and late April, there was a large amount of phlegm, and the peaking period of the pheasant was from late April to early May. After the emergence of the adult, it is the wheat heading and flowering period, followed by a large number of eggs (the yellow larvae are slightly earlier than the wheat red larvae).

The yellow-sucking larvae lay more eggs in the inner and outer buds of the priming wheat cultivars and on the side slices. One to produce 5 to 6 grains, and the egg stage is 7 to 9 days. The red-sucking larvae lay more eggs between the wheat spikes and the spikelets that have not been flowered, and one to three to five, and the egg stage is 3 to 5 days.

After the larva hatches, it is transferred to the husk, and attached to the ovary or freshly grouted granules to absorb the juice. After the old larvae are harmed, they climb to the husk and the awns, and fall with the raindrops, dew or automatic bombs on the soil surface, and drill into the soil at 10-20 cm for the summer and winter.

Factors affecting winter wheat sucking insects

1. temperature. The larvae are resistant to low temperatures and are not resistant to high temperatures, and the winter mortality rate is lower than that of summer. The overwintering larvae break through the cockroach at 10 cm soil temperature 7 °C, 12 ° C ~ 15 ° C phlegm, 20 ° C ~ 23 ° C emergence of adult worms, when the temperature rises above 30 ° C, the larvae return to sleep.
2. humidity. During the wintering larvae breaking activity and rising phlegm, the rainwater (or irrigation) emergence rate is high. When the humidity is high, not only the hatching rate of the eggs is high, but also the newly hatched larvae have strong activity and are easy to invade and bite. Before and after the wheat flowering, there are many rains, high humidity and moderate temperature, which often cause the occurrence of the larvae. Dry weather and low soil moisture are not good for it.
3. soil. The soil of the loam is loose and the water retention is strong. Clay is not good for its life, and sand is less suitable for its life. The red-sucking larvae prefer alkaline soil, and the yellow-sucking worms prefer the more acidic soil.
4. The adult period of the adult is coincident with the flowering stage of the wheat heading, and the dislocation of the two stages is light.

Winter wheat sucking insect control experience

For wheat fields where the larvae are severely affected, it is best to rotate with other crops such as cotton and rape to avoid the insect source. For the prevention and treatment of pesticides, the method of “one sprinkle and one spray” can be adopted: before the jointing of wheat to the booting stage, the acre is mixed with 50% phoxim 0.5~1 kg and 15-20 kg of fine sand (watering after spraying). To kill newly emerged adults, larvae and pupa;

During the period from the heading of wheat to the time of flowering, use a 4.5% cypermethrin and other pyrethroid pesticides plus 40.7% lesbian 800 times mixture (20 ml per sprayer), or “邯科 140” 1500 times solution (per sprayer 10) ML "single one") can effectively kill adult worms and eggs of the larvae, and can simultaneously treat wheat stalks and red spiders, with a spray and more treatment, and the control effect is remarkable.

Winter wheat sucking insect control measures

1. Agricultural control

(1) Selection of insect-resistant varieties

The midwifery is resistant to low temperatures and not to high temperatures, so the winter mortality rate is lower than the summer mortality rate. The soil moisture condition is an important factor for the wintering larvae to start activities, and is a necessary condition for the growth and emergence of the larvae. Different wheat varieties, wheat larvae have different degrees of damage. Generally, the awns are long and thorny, the tight ears are dense, the flowering period is short and tidy, and the varieties with thick rind are unfavorable for spawning, larval invasion and damage of adult larvae.

Therefore, it is necessary to use a wheat variety in which the shape of the ear is tight, the inner and outer pilose are long and dense, the wheat grain is thick, and the slurry is not easy to flow out.

(2) Rotation

Wheat fields have been turned over in recent years, and wheat and rapeseed, beans, cotton and rice crop rotations have a significant effect on the number of insects. In the severe field of wheat midge, and cotton and wheat intercropping or replanting crops such as rapeseed and garlic, it will be mitigated after planting wheat after the rainy year.

2, chemical control

(1) Soil treatment

Time: 1 before wheat planting, the last shallow tillage; 2 wheat jointing stage; 3 wheat booting stage.

Pharmacy: 2% methyl isoflavin powder, 4.5% methyl ester powder, 4% enemy horse powder, 1.5% methyl 1605 powder (this drug is a highly toxic pesticide that the country has banned), 2 to 3 kg per mu, Or 80% dichlorvos EC 50-100 ml plus water 1 ~ 2 kg, or 50% phoxim EC 200 ml, add 5 kg of water sprayed on 20 ~ 25 kg of fine soil, mix well to make toxic soil application, while sprinkling Plowing and turning into the soil.

(2) Adult disease control

Before heading from wheat to flowering, use 80% dichlorvos per acre, 150 ml, add 4 kg of water to dilute, spray on 25 kg of wheat bran and mix well, and sprinkle a pile per mu. This method has a long residual effect and good control effect. Or use 40% dimethoate (the drug is a highly toxic pesticide that has been banned by the state) 1000 times; 2.5% deltamethrin 3000 times; 40% chlorpyrifos WP 1500 times solution.

The website of this paper: The prevention and treatment of winter wheat sucking insects

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