Nocturnal moth: belongs to the Lepidoptera nocturnidae, a new pest in China's summer corn area, molting 5 times in the larval stage for a total of 6 years, afraid of light and high temperature, diurnal and nocturnal, with the hazard characteristics of the plant! The larvae are heterogeneous and can feed on more than 30 species of plants in more than 13 families, mainly endangering summer corn in our land. As the larvae age of the pest grows, the amount of pest food will continue to increase, and the scope of occurrence will be further expanded, if it cannot be controlled in time, it will seriously threaten maize production. Due to the similarity of its attack sites and morphologies, many farmers are accustomed to mistaking the two-point night moth for a "ground tiger". After the emergence of corn seedlings, some corn fields began to occur at two o'clock, and localities often mistakenly believed that it was a pest of ground tigers.
Adult 2-point nocturnal moth (one black and one white dot on the forewing)
Two-point nocturnal moth larvae and identification points
Ground tiger identification points
Comparison of the morphology of the two-point nocturnal moth and the small ground tiger:
Hazards of the two-point nocturnal moth to corn:
In recent years, wheat fields are generally straw returned to the field, the two-point nocturnal moth generally occurs more in the summer corn field of wheat stubble, and the distribution of pests in the field is uneven, but the border ridge near the ridge back occurs seriously, and the general flaky hazard area is about 4 square meters! The investigation found that the wheat straw bran cover was serious, the cotton and wheat flower arrangement field was serious, the sowing was serious, and the sowing ditch was shallow. Generally, mid-June is the peak of the occurrence of overwintering adults, and the larvae hatched by the overwintering adults in late June and July are moth-eating corn seedling stems, and this year it is predicted that the larvae of the two-o'clock nocturnal moth will occur in a large area from late June to early July.
The two-point nocturnal moth mainly harms corn seedlings with larvae hiding under the broken wheat straw around the corn seedlings or in the topsoil layer of 2-5 cm, mainly nibbling on the base of the corn stem, and the following symptoms can be formed according to the growth period of corn:
2-3 leaf stage hazards cause maize seedlings to die from root bite:
3-4 mm voids form at the base of the stem of moth-fed corn at the 3-6 leaf stage, resulting in wilting and death of corn heart leaves
At the 7-10 leaf stage, bite the secondary root or main root of corn, causing lodging, severe death, if not controlled, it will lead to a large shortage of corn seedlings, seriously reducing yield!
In the first half of this year, there was more rain than in the same period of previous years, the overall humidity in the field was larger, the base of insect eggs was relatively large, the climate was suitable for the hatching of insect eggs, coupled with the fact that the wheat harvest period this year was similar to the peak period of adult insect occurrence, the two-point nocturnal moth showed a high incidence trend, farmers in many areas generally feedback, the corn growth trend is poor, the straw, wheat bran where the growth is worse, pull out the plant and find that there are traces of insect pest bites at the base of the stem, so it is necessary to strengthen the control of the two-point nocturnal moth, and observe in the field. Whether the corn plants in the field have individual tilt or corn cob leaf wilting phenomenon, pull out the plants in time for observation, whether it is a symptom of the harm of the two-point nocturnal moth, and take early action to grasp the prevention and control.
The recommendations for prevention and control measures are as follows:
1, straw recycling, harvesting the base of the wheat stubble as low as possible, the use of straw recycling technology, to minimize the field of wheat straw, wheat bran and weeds.
2. Pharmaceutical prevention and control: In theory, the effect of shunlang irrigation in the field is the best, but it is limited by the actual situation, and the operation of irrigation is relatively difficult. Usually the corn seed secondary coating, field rooting or spraying, sprinkling granules, sprinkling granules as far as possible to choose a high content of agents, such as 1% thiamethoxamine granules 2 kg, mixed sandy soil sprinkling, along the ridge sprinkled on the edge of corn seedlings. Spraying or drizzling root can be used in combination with 12% beetlemonitrile or biphenylthiaciproazine. Or just sprinkle chlorpyrifos granules and water the corn before watering it.
In addition, adult insects that inhabit the wheat stubble must be killed, especially in the lodging wheat field, emphasizing 2 times of medication. In general, before sowing the seedlings, first go to the field again, such as startling moths and the number is large, please spray medicine immediately to kill. According to studies, spraying adult insects has a 90% anti-effect.