What are the environmental conditions for the development of locust eggs and mosquito eggs

Locust, Orthoptera, Acridoidea, has gone through three stages: egg, nymph and adult. Larvae and adult are similar in morphological structure and living habits, and they are incomplete metamorphosis and metamorphosis sexual reproduction. The development process of grasshoppers is different from that of silkworms. The larvae hatched from fertilized eggs of locusts are similar in shape and living habits to adults, but smaller in size, with immature reproductive organs, and only wing buds can jump, which is called jumping pupa. This larva is called nymph. After molting for five times, the nymph gradually grows up and develops into a winged and flying adult without going through the pupal stage. The duration and depth of flooding after spawning will affect the hatching rate of locust eggs. The soil is dry, the humidity is too high, and the mortality of locust eggs and larvae is high.

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Adult: the female worm is 3 1-40mm in length, with an average of 33mm；; Wings are 30-3mm long. Male worms are 29-35mm long and their wings are 24-25mm long. Their bodies are mainly green and their wings are longer than their stomachs. The antenna length of the female insect is 23mm, and that of the male insect is 25mm. The forehead protrudes like a triangle. There is an obvious yellow vertical stripe from the top of the forehead to the center of the chest backboard, which gets bigger as it goes back. The end of the antenna is light yellow. The front edge and middle part of the front wing are dark brown, and the buttocks are green. Yellow hind legs with black spots, both sides? Quot herringbone grooves are arranged neatly; Tibial joint is thin, with dark green surface and two rows of spinous processes, the outer row 14 and the inner row 15. The bottom of the thorn is light yellow and the end is dark. Abdomen 1 1, back purple-black, central ridge light yellow, abdomen yellow.

Egg: long oval, slightly curved, slightly pointed at one end, 6-8 mm long and 2-2.5 mm wide. Ochre yellow, with honeycomb net pattern.

Yellow-ridged bamboo locust 1 Adult 2. Eggs 3, 4. Jump.

1 year-old salamander: it is light yellow when it is first hatched, and turns yellow, green, black and brown after about 4 hours. The head is gray and the forehead protrudes like a triangle. The compound eye is dark gray. The tip of the antenna is light yellow. There are pale yellow stripes on the hind legs. There is a square black spot on both sides of the midline of the front end of the chest backboard, and a smaller black spot on the side of the backboard. There is a big black spot on both sides of the back chest plate. The fuselage length is 9.8- 10.9mm, with an average of 10.2mm, and the antenna 13- 14, with a length of 4. 1-5.2mm, with an average of 5 mm ... The rear edge of the front chest backboard does not protrude backward, almost in a straight line. The wing buds are not obvious, only the rear edges on both sides of the middle and rear backboard protrude slightly backward.

2-year-old bugs: the body color ratio 1 year-old bugs are yellow, especially the midline color of chest backboard and abdominal backboard. Body length 1 1- 15mm, with an average of12.1mm. The antenna is 18- 19, the length is 6.2-7.2mm, with an average of 6.8 mm, and the rear edge of the front chest backboard still does not protrude backward. The front and rear wing buds obviously protrude backward, and several wing veins can be faintly seen under the magnifying glass.

3-year-old: body-colored big-toe beer m ⑿⒏⒏⒏⒏⒏⒏⒏⒏⒏⒏⒏? Hey? What's wrong with the lawsuit? Tired? Song-Portuguese brigade reform? Rice? Lê？ 4.9- 18mm, with an average of16.4 mm. Antenna 2 1 section, with a length of 8.3-9.6mm, with an average of 9 mm. The rear edge of the front chest backboard slightly extends to the back of the body, covering a part of the middle chest. The wing bud is obvious, the front wing bud is long and narrow, the back wing bud is triangular and wider than the front wing bud, the wing vein is easier to see, and the wing bud is not folded on the back.

4th instar bug: The body color is the same as that of 3rd instar bug, the body length is 20-24mm, with an average of 21.4 mm. There are 23 antennae, the length is 12- 13.7mm, with an average of 12.6mm, and the rear edge of the front chest backboard obviously extends backward, covering one. The anterior and posterior pterygoid buds are folded backward, the anterior pterygoid bud is located in the posterior pterygoid bud, and the posterior pterygoid bud almost reaches the end of the first abdominal segment, and the pterygoid vein is clearly visible.

5th instar worm: The body color is the same as that of 4th instar worm. The body length is 20.8-30mm, with an average of 26.3mm, and the antenna has 24-25 nodes, with a length of 15.7- 17.6mm, with an average of 1 6.5 mm. The back edge of the front chest backboard extends extremely backward, covering most of the back chest, and the length of the upper edge is almost the lower edge/kloc. The wing buds are older than 4 years old and have reached the end of the third abdominal segment to cover the auditory organs. When feathering, the body becomes emerald green.

Biological properties

1 year 1 generation, overwintering as eggs in soil. In Hunan, the overwintering eggs began to hatch in early May of the following year, with the peak period from mid-May to early June and the end period in late June. Sometimes, individual eggs can hatch in early July. 1 instar pupae are abundant in mid-May, late May of 2nd instar, early June of 3rd instar, mid-June of 4th instar and late June of 5th instar. Adult began to emerge in early July, and reached its peak in late July, mating in mid-July, and mating peak in late July and early August. Mid-August is the peak of spawning. The spawning period in Laiyang, Hunan Province has been delayed to the end of June 65438+June 65438+June 65438+1early October. The pupation duration of 1 age is 9-26 days, with an average of 14.4 days; 2 years old, 7- 17 days, with an average of 9.9 days; The third instar is 5- 19 days, with an average of 9.6 days; 4 years old, 5- 14 days, average 10 days; The 5th instar is 7- 13 days, with an average of 1 1 day. The life span of pupae is 46-69 days, with an average of 52 days. The life span of female adults is 50-84 days, with an average of 69 days, and that of male adults is 54-56 days, with an average of 54.6 days.

After the egg is laid, with the development of the embryo, its color gradually darkens. When the compound eye, foot and single eye can be seen from the outside of the eggshell, it means 15- 19 days before hatching; The egg is reddish, and when the abdominal link is obvious, it means 7-8 days before hatching; When the head darkens and four brown spots appear on the front and rear chest backboards, there are still 3-4 days before hatching; Embryo development is completed, the whole egg is full, and it can hatch into pupa in 1-2 days.

The peak period of hatching eggs is 14- 16 every day, accounting for about 54% of the total number of hatched eggs, and few eggs hatch at night. Most of the eggs in the same egg block are hatched on the same day, and few of them are delayed until the next or third day. Generally, eggs on the south slope hatch earlier than those on the north slope, eggs on the mountainside hatch earlier than those on the top of the mountain, and eggs on the thin ground cover hatch earlier than those on the thick ground cover. The incubation period of whole eggs can be as long as 1 month. The hatching rate of eggs is about 89- 100%, with an average of 98%.

After hatching, the larvae gather in groups on bamboo and gramineous weeds, and they don't feed on the first day, but start to feed on the leaves of bamboo and gramineous weeds the next day, resulting in many notches on the edges. Feeding time is mostly 5-8 o'clock, 18-22 o'clock. During the period from 4th instar to mating, the food intake is the largest, especially at 5th instar, accounting for more than 60% of the total food intake. Generally, the jumping time on bamboo is 1 from the end of the second instar to the beginning of the second instar, but if the ground lacks small bamboos and gramineous weeds, the phenomenon of big bamboos will appear soon after hatching, and all bamboos will be planted after the third instar. After jumping on bamboo, concentrate on the tip to feed first, and then slowly disperse after three years of age. When it concentrates on eating bamboo shoots, bamboo shoots are often yellow and can be seen from a distance. Jumping insects have the habit of gathering and migrating, and adults have the ability to migrate. When the weather is hot, bamboo often goes to the shade at 8: 00, and after 17: 00, the temperature is lower and the bamboo is alive again. Jumping insects and adults rarely move from darkness until the morning dew dries. Fleas stop eating the day before peeling. Peeling is mostly at 6- 1 1, 8 o'clock.

The emergence time of adults is mostly 5-20 hours, and the peak time is 8- 10. The emerged adults also live in groups like fleas, and can fly well before the sexual organs mature. Migration is common on sunny or hot days. Rainy weather is not conducive to its flight. It generally takes 19-25 days from eclosion to sexual organ maturity, with an average of 20 days. Once the sexual organs mature, adults mate. The mating time is usually 5-7 or 17-2 1. It takes a while to lay eggs after mating; According to indoor observation, the longest time is 22 days, the shortest is 12 days, and the average is 16 days. Adults who start to lay eggs will eat less and only eat some leaves of bamboo shoots. Oviposition usually occurs at 2-6 o'clock.

The eggs are laid in the soil, and the depth of burial is about 3.3 cm. When laying eggs, the females first dig the soil with the ovipositor tube until the abdomen can be completely inserted, and then secrete a foamy white sticky substance, and then lay the eggs obliquely in this foamy substance layer by layer. After spawning, the upper end of the egg mass secretes some foamy substances. On this foamy substance, thick dark brown mucus is secreted. When the mucus hardens, it is a round and concave black egg cover. When the soil particles on the mulch are washed away by rain, they are exposed to the soil surface. A female can lay 1- 10 eggs in her lifetime, usually 6 eggs. On average, each egg block has at most 22.3 eggs and at least 14.5 eggs.

Eggs are mostly produced on the hillside of Zhushan Mountain or the hillside with little firewood and loose soil, and some of them are produced in the foothills. Because of man-made fishing, some people lay eggs in fir forests or other woodlands, but this is rare. Male adults die after mating, while female adults die gradually after laying eggs.

Both jumping insects and adults have the habit of liking salty taste and human urine.

The known natural enemy is the black egg bee. Parasitic eggs, the parasitic rate is 4.4%; Small parasitic flies, parasitic on fleas, parasitic rate of 4.4%; Large parasitic flies, parasitic on adults, parasitic rate11.4%; Red-headed turnip larvae eat locust eggs; Ants, spiders and insect-eating flies eat worms; Mantis preys on fleas and adults; Mites parasitize fleas and adults; Beneficial birds include white cheek noise, thrush, black face noise, bamboo chicken, crow and so on. Trichophyton sinensis (the pathogen of strangulated plague) and another entomogenous fungus parasitic in locusts.

The initial temperature of egg hatching is 12℃, but the optimum temperature is 16-35℃, and the optimum temperature is about 30℃. It is possible to hatch when the relative humidity reaches 70%, but the optimum relative humidity is 90- 100%. In nature, when the air temperature is 18℃ and the ground temperature is above 20℃, locust eggs may hatch whether it is sunny or rainy, and the temperature in sunny days is 23-26℃ and the ground temperature is 24-27℃. The optimum temperature for desquamation is 27-28℃ and the humidity is about 90%. The optimum temperature for adult emergence is 30-32℃ and humidity is 75%.

Wind has a great influence on the survival, flight and spread of bamboo locust. Bamboo farmers in locust areas have a proverb that "the east wind blows and the west wind harvests" and "locusts are only afraid of the west wind". The main reason is that the east wind occurred in March-May. With the east wind blowing, the weather gradually warmed up, and jumping off a building occurred around mid-May. The west wind mostly occurs in August-10, when the weather is getting colder and the life of locusts after mating and laying eggs is on the verge of death. Once the west wind blows, they will die early. When the bamboo locust flies and spreads, if there is wind blowing, its diffusion distance can be increased.

Based on the study of the life table of the yellow-ridged bamboo locust, a three-year average life table system model of the yellow-ridged bamboo locust was established, which provided a scientific basis for predicting the population growth and decline trend and formulating control strategies.

The study on the control index of yellow-ridged bamboo locust shows that it is necessary to control when the leaf loss of Phyllostachys pubescens is 10%. However, the control index is affected by many factors, such as the accumulation of bamboo leaves, the cost of control and the situation of different bamboo forests. Therefore, when applying this index, we must master it flexibly according to the specific situation.

Investigation and prediction of insect situation

Egg check: The eggs of the yellow-ridged bamboo locust are generally laid on the hillside with loose soil and few bamboos and weeds, or on both sides of the valley slope or path between two mountains. The spawning ground often has skull, chest backboard, hind feet and other remains. Generally, there are eggs in mountainous areas where bamboo leaves are killed and places with carrots; In addition, there may be egg lumps in places where bamboo and weeds are seriously damaged. There is a gelatinous and hard black disc-shaped covering on the top of the egg block, which can often expose the soil surface when washed with water.

Inspection: During the incubation period, in addition to observing the incubation date, place, area and density, we should also dig out the egg pieces to check the incubation rate and the development progress of the eggs. Eye spots are usually seen outside the eggshell and hatch after about 14 days. In the later stage of egg development, the phenomenon of abdominal segment and eggshell thinning can be clearly seen. It is very important to monitor flea activities and know the number of hatching. Generally, it takes about 10 days from the day when fleas are found to hatch (most fleas are at the end of/kloc-0 and the beginning of 2), otherwise it is difficult to control fleas.

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Distributed in Hunan, Sichuan, Jiangxi, Fujian, Guangxi, Guangdong, Hubei, Jiangsu, Zhejiang, Anhui and Yunnan.

Control methods of bamboo locust

1. Oviposition: mark the spawning period of the bamboo locust and draw a marking map, then dig out the small full section of the egg block and put it in a gauze cage to let the egg parasitic bees fly out, so as to achieve the purpose of oviposition and protection of natural enemies. You can also plant paulownia trees in the forest, cultivate red radish and eliminate locust eggs.

2. Weeding: before most of the flea beetles are unearthed but not on the big bamboo, take a bamboo broom to catch the flea beetles on the small bamboo, weeds or shrubs when the dew is still wet in the morning; Or spraying 3% trichlorfon powder or 2.5% methyl 1605 powder1.5-2kg per mu; Or spray 800- 1000 times of 50% malathion, 1000- 1500 times of 50% methamidophos or 1500 times of 80% dichlorvos after drying; Ultra-low volume spraying can also be carried out with insecticidal detergent; Or release Beauveria bassiana in locust egg fields, so that fleas are infected with Beauveria bassiana just after hatching and die.

When fleas have been planted on bamboo and even some adults have appeared, they can only be smoked with smoke agent. Use of Smoke Agent: Use Lindane Smoke Agent, the dosage is 0.5-0.75 kg per mu. When exhausting smoke, the wind speed should be below 1.5m/s, and the best time for exhausting smoke is from the early morning when the east turns white to before sunrise. You can also smoke around 2 1, but it is generally not used unless necessary because of the rugged mountain road and inconvenient movement. On a calm and cloudy day, you can smoke all day. For bamboo forests with dense trees, in order to facilitate the release of smoke, the flue should be cut off in advance. The position of the flue varies according to the topography of the spawning ground, so that the smoke can spread all the spawning ground to the top of the bamboo forest without being dissipated quickly. The width of the flue should allow a person to walk freely with the chimney in his hand. The smoke exhaust pipe can be made of bamboo tube, one end of the tube has a joint, and the handle is installed next to the bamboo tube at the other end, and the included angle between the handle and the tube body is slightly greater than 90, so that smoke will not rush to the smoker when exhausting smoke. The size of the bamboo tube can hold 2 kilograms of smoke agent; In areas where there are no bamboo tubes, other items can be used instead, such as iron tubes, wooden cases, cartons, etc., and flame retardant treatment must be carried out. Moving method is the most effective way to release smoke, but if the terrain is too complicated, moving method can be combined with fixed method, or only fixed method can be used. When moving, the smoker's moving direction must be perpendicular to the wind direction; When using fixed smoke exhaust, the chimney must be placed in the windward. Due to the influence of topography and wind speed, the flue gas flow has certain rules. When there is no wind, the smoke will slowly flow to the foothills, and when there is wind (within 1.5m/S), the smoke will flow with the wind and finally flow to the lowlands. In some cases, smoke from the foothills can reach the top of the mountain. In order to master the wind speed and direction, so as to release the smoke, a pinch of smoke agent can be lit before the smoke is released to determine the direction of the smoke. If the smoke is straight, it means there is no wind; For example, the wind speed slowly inclines to one side, within 1.5m/S; If the smoke flows away quickly, it means that the wind speed has exceeded 1.5m/S, and smoking is generally not suitable at this time.

3. Put the urine mixed with pesticides into a bamboo pot and put it into the forest to trap and kill adults.

4. Insect growth regulator technology for controlling Dendrocalamus flavipectus.

(1). Significance of using insect growth regulators to control bamboo locust.

A. To control bamboo locust, bamboo resources must be protected.

There are 355,000 hectares of bamboo forests in our province, mainly distributed in more than 30 bamboo-producing counties (cities). Bamboo is an economic forest tree species with short forestry production cycle. The economic benefits of bamboo in the main producing areas play a decisive role. For example, Guang Ningxian, one of the "Top Ten Bamboo Towns" in China, has 67,000 hectares of bamboo forests, mainly green bamboos. Since 1984, the annual bamboo output has reached 200,000-250,000 tons, and the total annual output value of bamboo industry has exceeded 1 100 million yuan since 1993. The development of bamboo industry has a great influence on the production, life and local fiscal revenue of the people in this county. Therefore, bamboo is known as the lifeblood of Guangning people. Another example is Nankun Mountain, Longmen County, where there are 3,700 hectares of Phyllostachys pubescens, accounting for one third of the total forestland area. The annual output of Phyllostachys pubescens is 500,000-600,000, with an output value of more than 3 million yuan, which is the main source of income for local farmers. However, bamboo production has been affected by the harm of bamboo locust. The annual occurrence area of bamboo locust in our province is about 6.5438+0.5 million hectares (the annual occurrence area of bamboo locust in China is 70,000 hectares). It is a very headache to prevent and control bamboo locust in bamboo producing areas, and it takes a lot of manpower and financial resources to prevent and control it every year. For example, in the year of frequent disasters in Guang Ningxian, the area reached 8,000 hectares. 199 1, mobilized the masses to go up the mountain to catch fleas, and * * * spent 330,000 yuan to buy 7,000 Jin. The former county bamboo office distributes more than 20 tons of' Lindane Smoke Agent' to bamboo farmers every year. Before Nankun Mountain 1997 in Longmen County, the annual cost of controlling bamboo locust was more than 654.38+10,000 yuan. Therefore, the prevention and control of bamboo locust is the need to protect bamboo resources and increase economic benefits, and it is also the urgent requirement of people in bamboo producing areas.

B. the origin of diflubenzuron used to control bamboo locust

Due to the good economic benefits of bamboo, the prevention and control of bamboo locust has been paid more attention, and the enthusiasm of the masses is also very high. Before the early 1970s,' BHC' powder was mainly used to control bamboo locusts, and later, highly toxic chemical pesticides such as lindane smoke and methyl 1605 were used, which have been in use ever since. However, the use of these drugs not only pollutes the environment and kills beneficial organisms, but also has high control cost, unstable control effect and incomplete treatment, which leads to years of control and disasters every year. In order to change this situation, the new technology of bamboo locust control was discussed. Through experiments, we screened diflubenzuron ⅲ from a variety of insect growth regulators. When it is applied to control young bamboo locust forest, the control effect is very obvious, and it can realize disaster-free control of bamboo locust. This medicine has a wide range of sources and low cost of prevention and treatment. Diuron ⅲ is a special pesticide, which mainly affects the normal growth and development of individuals by regulating and interfering with the synthesis of chitin in insects, leading to the death of pests and the decline of population density. The preparation can reduce environmental pollution, is safe for people, livestock and other beneficial organisms, and is beneficial to promoting ecological balance. Another characteristic of this pesticide is that it has strong adhesion on the surface of bamboo leaves, is resistant to rain erosion, is not easy to decompose, has obvious delaying effect on pests, and has good control effect on bamboo locust jumping in different incubation periods. The development and utilization of this drug has greatly improved the technical level of bamboo locust control.

(2) Experiment of controlling bamboo locust with insect growth regulator.

(A) test materials and methods

(1) 25% diflubenzuron III colloidal suspension and powder, 65,438+06% diflubenzuron III synergistic powder (including 65,438+04.5% diflubenzuron III and 65,438+0.5% Dolebao) are all produced by Guangdong Huizhou Zhongxun Co., Ltd.; Pesticide plant produces 20% pesticide wettable powder; 20% Youle wettable powder (made in Japan) is provided by Guangdong Academy of Agricultural Sciences; 5% carnosine emulsion was provided by Melamine (China) Co., Ltd.; 5% Yitaibao emulsion is a commercially available pesticide.

(b) Shake off the tested flea beetle aged 1 ~ 5 years from the green bamboo forest, cover it with white plastic film, raise it indoors in groups for 1 ~ 2 days, and then put it into a cage for experiment. Fleas are divided into three age groups:1~ 2,3,4 ~ 5.

(3) Indoor or forest efficacy test, using 100 mesh green iron net to make a cylindrical insect cage with a diameter of 20cm and a length of 45cm, and sewing 20cm long gauze at both ends for binding or triangular bottle cover.

(d) In the indoor efficacy test of insect feeding materials, the 1 year-old bamboo branches with tender leaves were inserted into a triangular bottle for hydroponics, and the bamboo joints were immersed in water. From the third day after application, replace the bamboo leaves without drugs every three days.

(V) Pharmacodynamic test method A finger-pressing small sprayer is used for pharmacodynamic test, and the bamboo leaves are sprayed until they are wet and do not drip; Powder (diluted with talcum powder according to weight ratio) is sprayed, wrapped with 4 layers of gauze, and then gently shaken off on bamboo leaves, and the powder is evenly distributed. The multifunctional plant protection machine "Kubota" made in Japan was used in the forest control experiment and large-scale control demonstration. The indoor efficacy test set 5 concentrations, and the 25% diflubenzuron ⅲ powder set 2 concentrations. In the forest efficacy test, each pesticide was treated with two concentrations; Forest control experiment: the dosage of 25% diflubenzuron III colloidal suspension is 300ml/hm2, spraying water is 25kg, the dosage of 25% diflubenzuron III powder and 16% diflubenzuron III synergistic powder is 300g/hm2, and talcum powder 15kg. Hang a cage in the forest before spraying to check the effect.

Blank control was set for all kinds of experiments, and each treatment was set up with three replicates (that is, three cages), 1 ~ 2, 3 and 4 ~ 5 age groups, and each cage contained 40, 30 and 20 larvae respectively.

(f) Effect check: the indoor efficacy test is checked once a day, and the number of dead insects is recorded until the mortality rate of the highest concentration treatment reaches over 95% or that of the control treatment reaches 20%; The forest efficacy test is checked every two days 1 time. Preventive effect of correcting mortality expression in cage test.

(g) Observe the persistence of diflubenzuron III in controlling bamboo locust.

In the demonstration site of Shi Jian Town, Guang Ningxian, the occurrence and control of bamboo locust were investigated from April to June in 1996 ~ 1998, and the spawning ground was investigated from August to June. The statistical area of small class files was investigated according to the second-class resources.

(2) Test results and analysis

(1) Indoor drug screening test. From 1995 to 1997, the indoor efficacy tests of 1-2-year-old fleas were carried out with five insect growth regulators and three formulations of diflubenzuron ⅲ. The results are shown in tables 1, 2 and 3.

It can be seen from the table that five insect growth regulators have obvious lethal effects on 1 ~ 2-year-old fleas. Except for the low concentration treatment of pesticides, Youle and several chemicals, most of them began to enter the death peak 5 ~ 7 days after taking the medicine. After 10, the mortality rate reached more than 70%; After 15 days, the mortality rate reached over 90%.

The lethal effect of 25% diflubenzuron ⅲ colloidal suspension and powder on 1 ~ 2-year-old fleas (table 1), through the significant comparison of the corrected mortality difference between them (P =

By analyzing the data in Table 3, the lethal concentration and lethal speed of diflubenzuron ⅲ colloidal suspension and powder to fleas were obtained (see Tables 4 and 5 for the results). As can be seen from Table 4, the LC50 and LC90 of synergistic powder are higher than those of colloidal suspension, and the efficacy seems to be inferior to that of colloidal suspension. However, the efficacy of Zengxiao Powder is only five days after taking the medicine, which only reflects the efficacy of the quick-acting components, and the main component Diuron III has not fully played its role; It can be seen from Table 5 that the time for killing 90% fleas by diflubenzuron and diflubenzuron is 65,438+07 ~ 65,438+08 days, while the time for killing 50% fleas by synergistic powder is faster, 65,438+0 times faster than that by colloidal suspension, which reflects the quick effect of synergistic powder and is consistent with the analysis results in Table 4.

In the past three years, the poisoning symptoms of this flea have been continuously observed indoors. The fleas treated with various drugs all showed symptoms such as slow movement, reduced food intake, slow growth and development, proctoptosis, abnormal molting, backward roll of tibial joint and final death. The poisoning symptoms of the dead insect net are special. After 7-20 days, fleas eat very little.

Because of the indoor efficacy test, only fleas can eat bamboo leaves with medicine for 3 days (bamboo leaves will not be sprayed later), which is definitely less than the dose taken in the forest. In addition, the activity range of fleas is obviously reduced after poisoning, and the growth and development are greatly affected. The mortality rate of fleas in the forest must be higher than indoors.

(2) Laboratory efficacy test of fleas of different ages. See table 1 for flea test results of different ages and concentrations. It can be seen from the table 1 that with the increase of flea age, the mortality rate decreased obviously after taking the medicine. In particular, the lethal effect of diflubenzuron with different concentrations on fleas aged 4-5 years is obviously lower than that of fleas aged 1-3 years. The lethal concentration and lethal time of fleas at different ages were further analyzed (see tables 8 and 9). The results showed that LC50 and LC90 increased significantly with the increase of insect age. In the same age group, the mortality rate increased with the increase of concentration. LT50 and LT90 were 4-5 days and 10-28 days respectively. When p =

(c) forest efficacy testing. In 1995 ~ 1996, the efficacy of 1 ~ 2-year-old fleas in the forest was determined with five insect growth regulators. The results are shown in Tables 6 and 7 and 10. As can be seen from the table, the determination results of various chemicals in the forest are similar to those in the room. Laboratory and forest efficacy tests showed that the concentration of diflubenzuron ⅲ was 125 and 250mg/kg, respectively. Compared with the powder with the concentration of 0.5% and 1.0%, there was no significant difference in the corrected mortality after 5 days, 10 and 15 days. The average death rate after 10 days was more than 90% when treated with diflubenzuron ⅲ with different concentrations, which could well control the harm of bamboo locust.

(d) comprehensive factor analysis. From the above test results, diflubenzuron ⅲ, carbendazim and Yitaibao all have strong lethal effects on 1 ~ 2-year-old fleas. Although the mortality rate of Buguiwang and Youle was low during the efficacy test period, they could inhibit the feeding, growth and development of fleas, eventually leading to individual death and population decline. However, because the mortality rate is slow and not obvious, it is difficult for production units to accept; At the same time, considering the cost of popularization and application, the price of diflubenzuron ⅲ is obviously lower than other chemicals, which is suitable for large-scale application; The diflubenzuron ⅲ colloidal suspension has strong adhesion and slow digestion speed (it is reported that the half-life of digestion speed on forest leaves is 48 days, and the total digestion after 60 days is only 62%), so it is very suitable for bamboo producing areas with long latent period of flea active period and heavy rainfall. The diflubenzuron ⅲ powder is easy to use, and the synergistic powder has a certain quick effect. Although the powder adhesion is poor, mastering the spraying weather can overcome this shortcoming.

(e) To observe the continuous effect of diflubenzuron in controlling forest bamboo locust. See Table 12 for the investigation results of recurrent areas of bamboo locust spawning grounds in recent three years and control areas in the following year.

From the table 12, it can be seen that through the comprehensive planning of 2247 hectares of bamboo forest in Shi Jian town, Guang Ningxian, the winter spawning area ratio of 1995 ~ 1997 decreased by 92.8% and 1997. The repeated occurrence area of the same subclass of bamboo locust in the control area is only 2.3 ~ 10.0%, and the source and occurrence area of bamboo locust have been greatly reduced, which has controlled the trend of large-scale occurrence and serious harm for many years.

(3) The technical points of diflubenzuron in controlling bamboo locust.

(1) Identify the insect situation and make a good forecast.

The investigation of insect situation mainly focuses on two periods: one is to investigate the spawning place of bamboo locust at the end of spawning (around September last year). According to the habits of bamboo locust laying eggs on the edge of the affected area, loose soil and less ground coverage, the insect areas and key occurrence areas of the next year can be preliminarily grasped by looking at the insect carcasses or digging locust eggs on the forest floor. Secondly, during the incubation period, it is found that newly hatched bugs are easy to be found when they feed on weeds or bamboo leaves. The hatching time, occurrence place and population density of fleas can be accurately grasped. Insect investigation requires a lot of manpower, which is usually combined with mobilizing the masses. In order to grasp the incubation period and unearthed time of fleas in advance, a prediction formula can be established according to the relationship between the temperature, rainfall and incubation period in1~ March (see Guangdong Forestry Science and Technology Phase IV). In Guangning demonstration site, another method is used to calculate, that is, according to the daily average temperature from late March to April 5 of that year compared with the same period of last year, the incubation period will be 2.6 days earlier or later than last year for every increase or decrease of 1 degree. The predicted incubation period of 1996 and 1997 is consistent with the actual incubation period, and the predicted incubation period of 1998 is affected by the special high temperature after April 5, which is two days earlier than the actual incubation period. In addition, the developmental duration of locust eggs can be used to predict.

Mosquitoes, Diptera insects, eggs, larvae and early pupae all live in water. Mosquitoes can't breed as long as their breeding water source is cut off. According to different temperatures, the incubation period of mosquito eggs is 7- 14 days. The optimum temperature is 20-30 degrees, and the development stops below 10 degrees. On condition that there must be water! ! !