Control techniques of lawn beetles

Maoming is located in the southwest of Guangdong Province with a warm and humid climate. There is a large area of lawn in the green space in the city, and the main varieties are Taiwan grass and big-leaf oil grass. These special geographical and plant conditions lead to the frequent occurrence of beetles in our city, and sometimes a large number of them, which do great harm to the plant growth and landscape of the public green space in our city. After years of practice, the occurrence and control techniques of lawn beetles in our city are introduced as follows:

1. Species and morphological characteristics of beetles: after years of observation, the seriously damaged species of beetles on the lawn of this city are as follows:

The main results are as follows: 1. The adult body is 10 mm 11.5 mm in length and 4.5 mm in width, long oval in shape, tan in color, dense chloasma scales all over the body, large compound eyes, 10 antennae, small shield triangular, 4 longitudinal lines and clamps on the sheath wing, obvious gray-white spots, large and small white spots composed of end protruding and lateral scales.

2. The beetle: the adult is about 10 mm long and 5 mm wide. Except for the sheath wing and small scutellum smooth and hairless, the whole body is densely covered with yellow and white fine pilose hairs. The back of the head and chest is copper and shiny; the sheath wing is brown, translucent and glossy, and the wing can be folded into a "v" shape from the sheath wing. There are rows of small dots on the sheath wing, yellow and white hair clumps on both sides of the abdomen, and sheath wings exposed at the end of the abdomen.

3. The four-grain golden turtle: the adult body is 7.5 to 12 mm long and 4.5 to 6.5 mm wide, and the body color is mostly dark copper green; the sheath wing is light brown to straw yellow, surrounded by dark brown to dark green, and the feet are dark brown; there are 2 white spots at the base of the buttocks, and one white spot on each side of the lower 5 segments of the abdomen, which is composed of dense fine hairs.

4. Black velvet golden turtle; the adult is 6-9 mm long and 3.5-5.5 mm wide, small, oval, dark brown to brown, densely covered with gray-black villi, smooth on the back of the head, 9 antennae, a few 10 nodes. There are 9 longitudinal grooves on the sheath wing and the chest web is densely covered with brown long hairs. The abdomen is smooth and each web has a row of hairs.

5. Copper green golden turtle: the adult body is 18-21 mm long, the body color is copper green and shiny; Coleoptera grass green, with 3 longitudinal ridges on each wing; yellow-green on the edge of forechest dorsal plate and sheath wing; antennae and feet yellowish brown; abdomen dark brown, densely covered with fine hairs.

Second, the harm of the beetle: the diet of the beetle is miscellaneous, the food intake is large, and the explosion is strong. Larvae (grubs) mainly harm the underground rhizomes of plants, such as Taiwan grass and big-leaf grass. After the root and stem of the lawn is damaged, the lawn turns yellow. if it is not controlled in time, the large area of lawn will die. On the other hand, the adults mainly feed on the tender leaves and flowers of the plant, resulting in irregular gaps or holes, and in severe cases, only leaf veins remain. Such as small holly, big-leaf crape myrtle, small-leaf crape myrtle, the leaves of wall-climbing tiger, and the blossoming flowers of canna (mainly four-striped golden turtles) are also harmful objects.

Third, the life habits of the beetle; the beetle generally occurs one generation a year from adults, eggs, larvae and pupae. The larvae move within 30 centimeters of the ground and dormancy within 30 to 50 centimeters of the soil when overwintering. From March to April of the following year, the temperature rose and the soil was moist. The overwintering larvae climbed from the deep soil to the shallow soil to pupate, and then feathered into adults. In the muggy evening, especially on the day when it turns clear after rain, a large number of adults are unearthed by Eclosion, and the peak of adult activity is from April to July. From August to September, adults lay loose eggs, humus-rich soil or accumulated barnyard manure, rotten weeds or fallen leaves.

Beetle larvae (grubs) prefer to grow in neutral or slightly acidic soil with a humidity of 15% to 20%. The beetle has a strong tendency to immature organic fertilizer, and the harm period is mostly concentrated in spring and autumn. Adults usually go out during the day and at night, and generally have phototaxis, pseudo-death and clustering.

The adult occurrence period of the five species of beetles mentioned above is mainly from April to August, and the key time for chemical control of adults can be set at late March, June and mid-August. In this way, it can be effectively controlled before the adult outbreak period.

IV. Specific prevention and control measures

The main results are as follows: 1. Agricultural control: (1) turn over the working soil in the green space where the grub occurs seriously. (2) avoid using immature organic manure. Because the beetle has a strong tendency to immature organic fertilizer. (3) selective application of chemical fertilizer. Such as ammonium bicarbonate, ammonium humate, ammonia, ammoniated calcium superphosphate and other chemical fertilizers, emit ammonia to avoid grubs and other underground pests. (4) controlling soil moisture. The most suitable soil moisture for grub development is 15%-20%. If the soil is too wet or too dry, the grub will transfer to the deep soil layer. If the soil is too dry or too wet for a long time, the eggs of the beetle will not hatch and the larvae will die.

2. Chemical control: (1) during the larval stage, 1000 times 50% phoxim EC or 1000 times 50% methamidophos emulsion can be used to irrigate the roots, irrigating 15 kilograms per square meter. Or sprinkle phoxim poisonous soil on the lawn, mix well with phoxim EC 400-500 ml per mu, add 3 kg of fine soil, combine with fertilization, mix and sprinkle on the topsoil, and then water to kill the larvae. The second chemical control was carried out 7 days later. Note that 2 days before the chemical application, the lawn can not be watered, keep the soil dry, can not be wet, the effect is better. (2) spraying to control adults. The prevalence of adult beetles is in late March, June and mid-August. The use of 50% fenthion EC 1000 times, 25% dimethoate EC 1500 times, 40% dimethoate EC 1000 times, 50% methamidophos emulsion 1000 times and so on play a good role.

3. Biological control: biological control mainly focuses on introducing natural enemies of underground pests and providing them with a good living environment, planting more nectar plants and using biological agents (such as BT emulsion) and chemicals that are safe to people, plants and natural enemies and do not pollute the environment (such as diflubenzuron). The natural enemies of beetles are birds, chickens, cats, hedgehogs and fart beetles, and the natural enemies that prey on grubs are insectivorous gadfly larvae. The natural enemies of parasitic grubs are parasitic wasps, parasitic mites and parasitic flies. At present, the main pathogenic microorganism that can effectively control grubs is Beauveria bassiana, and its control effect is up to 90%. The application of milk bacteria can cause some kinds of grubs to be infected with milk stink disease and kill them. In the United States and other countries, milk bacteria and their variants have been used to control grubs, and milk bacteria preparations Doom and Japidemic have been sold in the United States. The control dosage is 0.05 kg milky bacterial powder per 23 square meters. This kind of bacterial powder has 1 × 10 × E9 live spores per gram, and the control effect is generally 60% and 80%. This kind of environmental protection biological preparation should be actively promoted and applied in our country.