Vegetable spotted fly is a very small fly, adults are gray-black, adults use egg layers to stab the leaves to lay eggs under the leaf epidermis, the larvae moth eat the leaf flesh tissue under the epidermis of the leaves, forming a very obvious snake-shaped diving channel (commonly known as ghost drawing), when the insect path is covered with leaf surfaces, the function of the leaves is lost, and finally dried up. After the larva matures, it defoliates and pupates, and the insect is in full bloom from August to September.
<h1 class="pgc-h-arrow-right" > symptoms of harm</h1>
Larvae sneak into the leaves and petioles to eat leaf flesh tissue, leaving the epidermis, forming a snake-shaped tunnel, the chloroplast cells are damaged, reducing photosynthesis, seriously affecting the growth and development of plants, causing leaf shedding, plant death, causing yield reduction, affecting quality, reducing economic value, generally reducing production by about 30%, serious production reduction by more than 50%, and even ruining production.
Adults can also harm plants, female adults stab the leaves of parasitic plants, form white spotted thorn holes, and feed by laying eggs and sucking sap from the spots, the male adults cannot form spots, but can feed on the wounds caused by female adults. As a result, the leaf wounds are damaged, the leaf cells of the plant are damaged, the photosynthetic area is reduced, and the serious damage often leads to a large number of leaves withering and falling off, and the plant aging and even death. In addition, the activity of the insect body can also transmit a variety of viruses.
< h1 class="pgc-h-arrow-right" > life habits</h1>
Adult spotted flycatchers have a certain ability to fly, but are weaker and have strong yellowing. The optimal growth and development temperature is 20 to 25, growth and development are hindered when it is higher than 30 or less than 10, and the relative humidity of the most suitable growth and development is 75% to 80%.
< h1 class="pgc-h-arrow-right" > occurrence</h1>
Spotted flies occur several generations a year, overlapping generations are severe, and generations in greenhouses are even more chaotic. Spotted flies generally begin to occur in mid-to-late April, and may to October are the peak of occurrence, which is very harmful. The main factors that affect the occurrence of spotted flies are temperature, humidity and feeding. The development period of spotted fly larvae is generally 38 days. The insects are divided into 3 instars, the adults are active during the day, and 12 days after feathering, they begin to lay eggs.
< h1 class= "pgc-h-arrow-right" > control method</h1>
1. Strengthen plant quarantine and strict plant quarantine to prevent the long-distance spread of spotted fly divers, and deal with spotted fly larvae, eggs or pupae in the transportation of vegetables and cut flowers in a timely manner to prevent long-distance spread, and it is strictly forbidden to transfer vegetables and flowers from the epidemic area.
2. For the affected vegetable fields, the remaining plants and fallen leaves are burned centrally or piled up and buried deeply. Immediately after the vegetables are harvested, they are turned deep into the pupae of the topsoil spotted fly so that they cannot feather.
3. Insert yellow card to hang yellow strips to trap adult insects For spotted fly adults, there is a tendency to yellow, in the peak period of adult insects, in the shed and around the open vegetables or in the field of vegetables or in the field to insert yellow strips to trap adult insects.
Yellow card making method: use rectangular cartons or cardboard to coat the front and back of a layer of motor oil to make a yellow card, use bamboo sticks as supports to insert around the vegetable field or wear wire to make a tag, hanging inside and outside the shed or on the shelf.
4. Insect nets can be installed in the shed of the facility to fundamentally hinder the entry of leafminer flies. We can also use fly-killing paper to trap adult insects, in the early to late adult period, there are an average of 15 booby-trap points per acre, and 1 sheet of fly-killing paper is installed at each point for booby-traping adults, and 1 sheet is replaced in 3 to 4 days. Or release the ji small bee, anti-jaw cocoon bee, submarine cocoon bee, etc., these three kinds of parasitic bees are relatively high for the prevention and control of spotted fly parasitism.
5. Chemical control grasps the medication time, selects the peak period of the young larvae, and selects the principle of high efficiency, low toxicity and low residue. Optionally, 10% pyridoxine, arviercide, avermectin + amine can be used once every 5 to 7 days, and various agents should be used alternately to avoid resistance.