The two-point nocturnal moth has appeared! Summer corn growers should be careful!

Spodoptera litura, which must be no stranger to corn farmers, is a new pest in the summer corn area of China. At the same time, if there is no timely prevention and control measures, the spread of this pest is very fast, and in serious cases, it will lead to the extinction of a large area of cornfield.

According to the detection of the provincial plant protection and quarantine station, the number of overwintering generation moths is on the high side this year. At present, the two-point armyworm has entered the period of occurrence of the second generation, which is the main damage in the whole year. At present, Spodoptera litura has occurred sporadically in Hebei, Shandong and other places in China, and has not yet broken out in the whole country (according to Shandong, Hebei and other plant protection stations predicted that the peak period of the second generation larvae is about June 28-early July), so, prepare in advance, pest control and seedling protection is an important means to ensure the health of the whole maize seedling.

(Spodoptera litura)

Missed the best period of prevention and control. Therefore, it is very important to recognize the morphological characteristics.

The larvae of Spodoptera litura are 1.4-1.8 cm long, yellowish gray or dark brown, characterized by an inverted triangular dark brown stripe on the individual segment and two brown dorsal lines on the back of the abdomen until the sternal segment disappears. There are many kinds of ground tiger, but the basic characteristics are similar. The body length of the last instar larva is 3750mm and the head width is 3mm-3.5mm. The color of the body is dark, ranging from yellowish brown to dark brown, with dark brown longitudinal bands on the back and rough epidermis, full of small particles of different sizes. Please carefully observe the characteristics before prevention and treatment in order to prescribe the right medicine to the case.

Bite the wormhole at the root

The reasons for this year's outbreak are:

The main results are as follows: 1. The anastomosis degree of maize seedling stage and larva damage stage is good, and the field growth environment is favorable.

The harvest time of wheat this year is close to the peak of adults, and the oviposition environment of adults in the field is better. The sowing time of summer maize in most areas is close to perennial, and the seedling stage is in good agreement with the peak period of larval damage. Mechanical harvesting of wheat is widely used in all provinces, and the ratio of wheat bran and straw to the field is more than 90%. The higher mulch thickness in the field provides a suitable environment for adult oviposition and larval development. The measures of sowing and clearing ditch in some areas can reduce the damage of corn.

2. Most of the meteorological conditions in Huang-Huai-Hai are beneficial to the occurrence and harm of Spodoptera litura.

According to the monitoring and forecast of the National Meteorological Center, in the first half of June, the precipitation in most of Huang-Huai and parts of North China was 50% to 1% less than that in the first half of June. In the next 20 days (June 16 to July 4), the rainfall in Huang-Huai and most parts of North China is 3-70% more than that in the same period of the year, and the local amount is more than 1 times, which is beneficial to the occurrence of Spodoptera litura. The weather of more than 35 ℃ will occur in some areas, which can inhibit the oviposition, egg hatching and larval development of Spodoptera litura to a certain extent.

Control methods of Spodoptera litura

1. Ecological prevention and control: clear wheat straw in the field, ploughing or rotary ploughing in wheat field, and clear wheat straw in corn sowing line.

two。 Physical measures: hanging two-point nocturnal moth sex attractant in the field, adding insecticidal lamps, trapping and killing adults and reducing the number of eggs in the field.

3. Chemical control: killing adults.

In the field that has not yet occurred, it is recommended to use field spray such as cypermethrin, permethrin and permethrin, which can be combined with pre-seedling herbicide whole-field spray, or high-chlorine carbaryl salt + post-seedling safety herbicide 3-5 leaf stage whole-field spray prevention. If it has happened sporadically, spray corn rhizome with high-chlorine metovitamin salt, metamitrazide, indenyl, chlorobenzamide and other agents to achieve the purpose of insect control.

(2) bait: when Spodoptera litura larvae reach the 3rd instar, 4-5 kg of fried wheat bran or crushed and fried cottonseed cake can be mixed with 90% trichlorfon mixed with a small amount of water, or 480 g / L chlorpyrifos EC 500 g / liter of chlorpyrifos EC to become poison bait, sprinkle along the ridge on the edge of corn seedlings in the evening.

(3) poisonous soil: use 80% dichlorvos EC 300-500 ml or 48% chlorpyrifos EC 500 ml, 20% chlorpyrifos phoxim and other agents with contact and fumigation effects per mu, mix appropriate amount of water into 25 kg fine soil, or mix 25 kg fine soil with 5% chlorpyrifos granules and phoxim granules, sprinkle them on the base of corn seedlings in the early morning. Be careful not to sprinkle poisonous soil on corn plants. It should be used at an interval of two days after weeding to avoid drug damage.

Note: the spraying time should be before 9: 00 a.m. or after 5: 00 p.m. In sunny days, and spray in time in case of rainy days. Spray should be uniform and thoughtful, and weeds in the fields and roadsides should be sprayed. When the age of the insect is older, the dosage should be increased appropriately. Try to avoid high temperature period of application, in order to prevent personal poisoning, crop drug damage. The use of organophosphorus pesticides is prohibited for 7 days before and after spraying nicosulfuron herbicide.

(4) pouring medicine with watering. Corn fields that need to be watered can be irrigated with water, and 52.25% chlorpyrifos or 48% chlorpyrifos per mu can be irrigated into the field. Spray irrigation of corn seedlings, you can unscrew the sprinkler, plant-by-stem dripping liquid, pay attention to a large amount of medicine, to ensure that the corn root 30cm around the hiding place of pests.

-

More hot agricultural news, more practical agricultural technology, and more colorful interesting stories about farmers' lives are all on the Wechat official account of "Agricultural Medical Information" (WeChat account: newsonline1 ← can be copied by long press)

Reprint must obtain the consent of the author of this headline number and may not be reproduced without authorization.