Vegetable farmers who have been planting vegetables in facilities for many years, every time they are caused by greenhouse whiteflies, they encounter greenhouse whiteflies, vegetable production is seriously reduced, frequent spraying but little effect, how to prevent and control greenhouse whiteflies in the end to be effective? Try the whitefly predator Litch wasp, take the way of insect treatment, not only the effect is remarkable, but also the vegetables and human green pollution-
Greenhouse whitefly harms the leaves
Greenhouse whitefly, commonly known as the little white moth, belongs to the family Haphaeae. Occurs throughout the year, omnivorous, with the dry season from early autumn to late spring as the peak period, the temperature is too high or too low and the long-term rainfall and humidity are not conducive to its growth, with March to June and September to November as the peak of the occurrence, 26 ~ 28 ° C warm winter and facility planting is the most suitable for its development.
The egg stage of whitefly in greenhouses is about 5 days, the nymph stage is about 15 days, the adult life span can reach 1 to 2 months, and it takes only 19 to 27 days to complete a generation. Adults lay eggs on the back of the leaves of the plant, the mother worm produces up to 200 to 300 eggs, the nymphs after hatching have four instars, one year has sufficient, looking for a suitable host; after the second instar the foot degenerates and solidifies in the middle and old leaves to suck the liquid in the plant by the stinging mouthpiece, and after feathering, the adult worms continue to harm or fly to the dorsal tissue of the new shoots of other plants to lay eggs. Adult insects are not good at medium- and long-distance transmission, and when disturbed, they still return to the original crop habitat hazard after a slight hovering in or around the upper end of the plant, and generally rely on wind to spread.
Greenhouse whitefly harms plant leaves
Both adult and nymphs of the greenhouse whitefly can suck on the branches and leaves of the crop, and after the crop is damaged, the leaves fade green, turn yellow, wilt or even die. In addition, in addition to directly sucking plant nutrients, adults and nymphs will secrete a large amount of secretions, lure ants or other insects, seriously pollute leaves and fruits, and can induce the occurrence of coal pollution. The leaves or fruits of the plant are sprinkled with a layer of vinyl, which affects photosynthesis, causing poor quality of vegetables or fruits, losing the value of commodities, and seriously causing waste farming. In addition, whitefly can also transmit viral diseases, such as tomato victimization, early leaf fall, leaf rolling disease or spot wilting disease, fruit hardening deformity and so on.
The harm range of whitefly is particularly wide, with more than 700 crops recorded, and important crops for facility vegetables are tomatoes, eggplant, peppers, cucumbers, cabbage and other vegetables, as well as flowers and fruits. The harm to shed crops can reach 20% to 30% of different degrees of yield reduction every year.
Because the body surface of the greenhouse whitefly is covered with a layer of wax powder, it is difficult for insecticides to penetrate into its body, coupled with the incorrect use of drugs by farmers, resulting in frequent spraying but always unable to prevent whitefly, and due to the large use of chemical pesticides, whitefly have developed resistance, which makes it more difficult to prevent and control greenhouse whiteflies. Due to the wide range of greenhouse whitefly hosts and strong reproductive ability, the key is that the speed of diffusion is particularly fast, and the average farmer really has no way to take it.
Tomato coal pollution caused by whitefly in greenhouses
Many farmers are accustomed to seeing whitefly, the first thing that comes to mind is to spray, but the effect of spraying is very small, so how to prevent and control greenhouse whiteflies? Try the natural enemy of the greenhouse whitefly, the Aphid Wasp! Li aphid Xiaofeng is a whitefly that cannot be killed by pesticides, can it be effectively controlled?
There are natural enemies in all things in the world, and greenhouse whiteflies are no exception, and "insects for insects" is a way to use parasitic and predatory insect predators to eliminate pests. The natural opponent of the greenhouse whitefly is the aphid wasp.
Aphid wasps, Hymenoptera, Aphidaceae, an insect of the genus Aphid Xiaofeng, is widely commercialized around the world for controlling greenhouse whiteflies, known as the natural enemies of greenhouse whiteflies.
The adult wasp is a tiny size, only about 0.6mm, when we look at it with the naked eye, we can only see a small black dot, it is difficult to see its appearance, and the enlarged aphid peak is somewhat similar to the fly. So how does Lisa Xiaofeng control whitefly?
Treatment of whiteflies by lice aphid wasps
Lily aphid Xiaofeng is a parasitic bee specially parasitic in the body of whitefly, through the visual and taste to find the affected crop, lay its eggs in the body of the whitefly nymph, by eating the body fluids of the whitefly nymph, and complete the development from larva to pupa in its body, thereby killing the whitefly nymph, and the whitefly nymph after being killed gradually turns black. After about ten days of growth and development in its body, lice xiaofeng pupates into adult worms, and then breaks out of the cocoon of the whitefly nymph, and then looks for new whitefly to lay eggs and reproduce, so that the cycle is repeated, so as to achieve the purpose of preventing and controlling greenhouse whitefly.
In order to facilitate carrying and use, scientific research units or manufacturers generally make bee cards of the aphids, and vegetable farmers only need to bring the bee cards back to the shed and hang them on the plants of the crop. So what are the precautions when using aphid wasps to control greenhouse whiteflies?
The use of whitefly wasps to control whitefly grasps three key words:
1. Prevention in advance
There are two main measures for early prevention: the first measure is to choose a robust insect-free cleaning seedling, before colonization, install 60 insect-proof nets in the upper and lower air outlets and doorways of the greenhouse to prevent external whitefly from entering the park; the second measure is to evenly hang a small amount of yellow plates in the greenhouse after colonization, generally hanging about 20 pieces per acre, once it is found that there are whiteflies on the yellow board, no matter how many, it should be used in time to control the lice bees.
2. Know thyself and know thyself
The use of aphid wasps to control greenhouse whitefly, generally in the crop colonization for about 10 days or the yellow plate detects the occurrence of whitefly insect infestation, began to release bee cards, each acre of land each time need to release 2000 lice wasps, every 7 to 10 days to put once, continuously put 3 to 5 times. However, it should be noted that if there are too many whitefly lice in the greenhouse, the cost of releasing a large number of lice wasps is too high, so it is not recommended to use lily wasps for control, but to use biological pesticides or chemical pesticides to control.
3. Platooning
Whitefly like to feed on the young leaves in the upper part of the crop, so the eggs are generally laid on the leaves of the middle and upper parts of the crop, and the aphid wasps are hung in the upper part of the plant to avoid light, which is conducive to the survival of the aphid wasps and the spawning parasitism of the aphid wasps.
It should be noted that if aphid wasps are released in the shed, the insecticide cannot be used, because the insecticide will kill the aphid wasps. In addition, the aphid wasp also has requirements for the temperature and humidity of the shed, the temperature during the day should not exceed 30 ° C, the night temperature should not be lower than 10 ° C, and the humidity should be controlled at 60% to 70%.
In short, the greenhouse whitefly has a wide diet, a high reproductive rate, can be spread with the wind, the prevention and control work is slightly inattentive, and the virus is easy to spread rapidly. By using aphid wasps to treat insects with insects, it can not only prevent and control the stubborn disease of whitefly in greenhouses, but also reduce pesticide residues and pollution, which can be described as a double victory.