In recent times, there may be careful citizens who have discovered it
On the trunks of poplar trees within the green forest belt of our city
Hanging with a paper bag,
It says – insect predators
Chow's bees
Put the bee bag
Don't be frightened when you hear "bees"!
This is the secret weapon of pest control
There is no harm to trees or humans!
Let's listen to the landscaping experts to explain it~
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As an excellent fast-growing greening tree species, poplar trees have a large planting area in our province. Our city is mainly distributed on both sides of the highway, both sides of the township road and both sides of the river, which is characterized by rapid growth and strong adaptability, and its wood can be used as pulp, processing plates, etc.
However, in recent years, due to the single species of poplar trees, the expansion of planting area and climate, the harm of diseases and insect pests, especially leaf-eating pests, has become increasingly serious. The Yang Fanzhou moth is one of the most important pests. Yang Fanzhou moth can eat all the leaves in a short period of time, resulting in the phenomenon of "summer tree winter scene", which not only seriously affects the growth of poplar trees, but also destroys the ecological environment to a large extent, and hinders the greening effect.
Poplar trees are tall, so manual spraying is difficult to reach, and traditionally people use aircraft spraying, high-pressure spraying and trunk spraying methods. Although the control effect of these methods is good, for non-large areas of forest areas, there are problems such as high cost, pesticide waste, environmental pollution, and complex operation. With the improvement of people's awareness of the environment, the biological control of poplar pests has been paid more and more attention, and the use of Zhou's rodent wasp to control Yang Fanzhou moth is one of the more successful methods in recent years.
▲ Zhou's little wasp under the microscope
In order to effectively control the main leaf-eating insect pest of poplar trees, yang fan boat moth, in recent stages, the city's greening workers have successfully released nearly 2,000 Zhou's small bees and pupae in the public green space planted with poplar trees in the whole city, and each pupa can release 4000-6000 heads - Zhou's wasps.
It is a dominant parasitic wasp with high parasitic rate and strong fecundity, sensitive to lepidoptera pests (such as Yang Fanzhou moth, American white moth, Elm poison moth, willow poison moth, Yang Xiaozhou moth, large bag moth, national locust inchlust), can stab the egg layer into the American white moth and other pest pupae, and develop and grow in the pupa, absorb all the nutrients in the parasitic pupa, known as the "forest guard".
Zhou's little bee is only about 1 mm long, without bee needles,
There is no harm to trees or humans.
Here, appeal to the general public,
If you see a paper bag hanging from a poplar tree,
Don't pick the tulip pupae on the tree out of curiosity,
So as not to affect its lethality to pests!
Yang Fanzhou moth
First, the distribution and harm of Yang Fanzhou moth
Also known as poplar Tianshe moth, poplar Tianshe moth, distributed in northeast, north China, northwest China, central China, east China, south China and other provinces, municipalities and autonomous regions, foreign distribution in the former Soviet Union, Japan, North Korea, India, Sri Lanka, Indonesia, Thailand and European countries. Yang Fanzhou moth is the main leaf-eating pest of poplar trees, especially likes to eat the young leaves at the top of poplar trees, and then transfer to eat the middle and lower leaves after eating, and when severe, the leaves can be eaten. If poplar trees are repeatedly damaged, they cause early leaf defoliation, and in the event of drought or freezing, the treetops and branches are extremely susceptible to death.
Second, the morphological characteristics of yang fan boat moth
The Yang Fanzhou moth consists of 4 morphologies: eggs, larvae, pupae and adults.
1. Eggs:
Semi-oblate round, 0.9 mm in diameter, orange-red at the time of initial birth, dark gray near hatching;
2. Larvae
The old mature larvae have a black-brown head, fine white hairs on the body, gray-yellow-green on the back of the abdomen, and 8 orange-red tumors arranged in a circular arrangement at each section, with larger melanomas on each side, and a larger red-melanoma in the center of the back of the first and eighth segments of the abdomen.
▲Young larvae
▲ Middle-aged larvae
▲Advanced larvae
3. Pupae
The pupal is 13 to 18 mm long, brown, and bifurcated at the end of the gluteal spine. The cocoon is oval, off-white.
▲ Yang Fanzhou moth pupae
▲Yang Fanzhou moth before pupating
4. Adult insects:
Adults vary in size from male to female , with grey-brown bodies and a brown fan-shaped spot at the apex of the wing surface.
Third, the life habits of Yang Fanzhou moth
The number of generations of Yang Fanzhou moth varies from place to place, and there are about 5 to 6 generations a year in our city. It is currently in the third generation of advanced larvals (early August).
It overwinters in a cocoon on the ground,at the base of a tree trunk or at the foot of a stone crack wall,' and begins to feather into adults in April of the following year, with the first generation of larvae appearing in early May and then occurring about once every other month, with overlapping insect states during the same period, and the mature larvae forming cocoons and pupating overwintering in late September.
Adults are quiet during the day, active at night, and have strong phototropism. Eggs are laid on the same day after mating, and overwintering adults lay eggs on the trunk, laying 200 to 600 eggs per female, with an egg stage of about 10 days. The larvae molt 4 times, a total of 5 instars, the hatching larvae have clusters, often dozens or hundreds of heads gather on the leaf surface to peel off the leaf flesh, so that the leaves become a network; after 2 years of age, spit silk leaf adult buds, lurking in the buds during the day, buds out at night to feed; after 3 years of scattered feeding, when the food is insufficient, the spit silk migrates to other places with the wind, and then rolls the leaves as a pest. The old mature larvae spit silk knots in the curly leaves and pupate, and the pupal stage is generally 8 d except for the overwintering pupae.
1. The reproduction of Zhou's wasps
Zhou's wasp genus Hymenopterae wasp family Ji small bee family, currently mainly using tulip pupae for breeding, using the "three knives to break the cocoon method" to select good health, low degree of development of the tulip silkworm pupae as a propagation material, each pupae can produce 4000 ~ 6000 bees, sometimes up to tens of thousands.
Second, Zhou's wasp control Yang Fanzhou moth
1. Beekeeping period
Bees are released in the pre-pupal stage and early pupal pupal stage of the host's old mature larvae (currently the third generation of mature larvae pre-pupate and pupal stage). The Chow chick wasp searches for the host during the host's mature larval stage and crawls among the hairy bushes attached to the host body, stinging the host, prompting it to pupate early. After the host pupates (the wasps are wrapped in a pupa), they lay eggs in the host pupae, or they can directly bite through the host cocoon to reach the pupal to lay eggs.
2. Bee release time
When releasing bees, choose sunny and windy weather, the temperature is above 25 ° C, the time is between 10:00 and 16:00, at this time the light is sufficient, the humidity is small, it is conducive to the flight of the small bees to find the host spawn parasitism, Zhou's wasp flight ability is strong, the horizontal flight distance is about 45m at a time, and the vertical flight is about 35m. Bee colonization on rainy days should be prohibited.
3. Put the amount of bees
Zhou's wasp, 1 pupa can release 4000-6000 heads of small peaks, of which 85% are female bees, 1 female bee can parasitize and destroy 1 Yang Fanzhou moth pupae (parasitism rate of about 40-50%), in the wild when releasing bees should be based on the yang fan boat moth population density to determine the amount of bees, in addition, various unfavorable factors in nature will have an impact on the parasitism of small bees, so the actual amount of bees released should be larger than the theoretical value. Generally, the release of 3-5 tulip pupae per acre can achieve effective control.
4. Method of releasing bees
Use a pin or pushpin to fix the bee bag that is about to be filled with the bee pupae on the trunk (the orientation is not limited), and the hanging height is about 1.5-2 meters, so that the bees can feather out on their own. This method is easy, uniformly released and suitable for large area applications. The conservation unit needs to be released as soon as possible after being assigned to the tulip pupae (preferably on the same day, but the next day at the latest). It is forbidden to place bee pupae on the ground to prevent natural predators such as ants from eating and affecting the bees. The development age of Yang Fanzhou moth is not neat, and there is a phenomenon of generation overlap, which can be released twice, or the pupae of different bees during the development period of small bees can be mixed to release bees at one time. Generally, the release of 1 tulip silkworm pupa per mu can achieve effective control (such as the density of pest population is large, which can be increased to 3-5 bee pupae per acre).