Recently received a consultation, said that the Bermuda lawn in a short period of time a large area of yellowing, some even died, I suggest rushing to the grass in the early morning or evening to observe, to see if there are insects or insect feces on the surface, the feedback is that there are insects and insect droppings. That's right, it was the Pale Sword Night Moth that began to harm.
The pale-sword nocturnal moth, also known as the rice small gray nocturnal moth, is an insect of the lepidoptera nocturnidae, which is one of the main pests of lawns, and endangers the grasses of high fescue, early maturing grass, ryegrass, Manila, Bermuda, paradise grass and other grasses with larvae. Its distribution is widespread, almost all over the country lawn has occurred, the harm is more and more extensive, the harm to the lawn is also more and more serious.
1. Morphological characteristics
The larvae hatch are grey-brown and green after feeding, and the old mature larvae are cylindrical, with a light brown oval head, a black "eight" pattern along the molting line, and a pink flesh in the dorsal midline. Pupae are green at first, and then gradually turn reddish brown, with 2 gluteal spines, parallel. The larvae are suspended dead and curled in a "C" shape when shaken. The adult body is pale greyish brown, the forewings are grayish brown, and the hindwings are pale grayish brown and wider than the forewings. Male adult antennae are pinnate, female adult antennae are filamentous.
2. Occurrence of regularity
Due to the vast territory of Our country and the large difference in climate, there are also differences in the occurrence of the light sword night moth, taking Shanghai as an example, the light sword night moth occurs 4-5 generations a year, with old mature larvae and pupae overwintering in the shallow soil near the root of the lawn grass. There is generational overlap, with the first generation of larvae infested from early May to mid-June, the second generation from late May to mid-July, the third generation from late June to early August, the fourth generation from mid-July to late August, and the fifth generation from mid-August to mid-October. The fourth and fifth generations of larvae occur in the largest amount and are the most harmful.
Therefore, July to October is the key period for lawn carers to prevent and control. Adults of the pale sword moth are feathered at night, have strong phototropism, hide in the lawn during the day, and make short-distance migrations if frightened. The hatching larvae feed in swarms, crawl around in shock or fall to the ground to fake death.
3. Hazard characteristics
The larvae are infested day and night before the third instar, and after the third instar, they are diurnal and nocturnal, and they can be harmed all day on cloudy days. The larvae of 1st to 3rd instar eat very little, eating only leaf flesh, leaving the epidermis and leaf veins, white and transparent, resembling a skylight. After entering the 4th age, especially the 6th age, the amount of food is large, and when it enters the binge eating period, it can eat all the leaves and stems of the lawn grass in just a few days, forming a large bald spot. If the prevention and control is not timely, all the leaves will be eaten in just two or three days, and a large number of elderly larvae will crawl to the highway in groups, which will affect the green environment and health.
The growth and reproduction of the Agaricus moth is greatly affected by temperature, humidity and grass volume. High temperature, dryness, and sufficient amount of grass are conducive to its growth and reproduction. In addition, the occurrence of the pale sword moth varies greatly from year to year. Different lawn lots in the same year also have large differences, and locality occurs significantly. Generally, the 3rd to 4th generations from July to September every summer occur the most, and it is very easy to erupt on the lawn.
4. Prevention and control methods
(1) Artificial control: from July to September, regular inspections should be carried out (every 10 days or so) to know the peak period of adult egg laying, and when the larvae hatch, the lawn should be mowed and the egg blocks should be cut at the same time, and the centralized destruction treatment should be carried out.
(2) Physical control: using the phototropism of the adult insects of the light sword night moth, pay attention to the places with large light density in the surrounding environment, such as around buildings, street lamps, and landscape lights, as the focus of prevention and control, and use black light lamps to trap adult insects.
(3) Chemical control: When insect infestation occurs, 5% methyl vitamin salt 1500 times liquid, 20% methyl vitamin indigovirus 2000 times liquid, cabbage nocturnal moth karyotype polyhedravirus 500 times liquid spray, it is recommended to use medicine in the early morning or evening. In addition, due to the general growth of grass lawns in July to September, the lawn density is relatively large, it is recommended to carry out a low pruning of the lawn before medication, and the water consumption must also be sufficient, and it can be evenly penetrated in order to play a better control effect.
Source: China Flower News