There are many host crops and the harm degree is heavy. Among them, citrus fruit fly is a supplementary agricultural plant quarantine pest in Jiangsu Province. In autumn, fly pests harm many fruit trees such as late maturing peach, pear and date, persimmon, pomegranate, citrus and kiwi. Adult insects Pierce the skin of fruit with ovipositor to lay eggs, and larvae eat the flesh after hatching in the fruit, causing the fruit to turn yellow, rot and fall off, which has a great impact on the yield. In recent years, the planting area of citrus fruit trees and other facilities in our province has been increasing, providing rich food sources and wintering places for real fly pests, and the harm of real fly occurrence has a rising trend. According to the survey across the province, since September, the number of adult fly pests has continued to be high, and the rate of insect fruit in local orchards has reached more than 10%, which is a heavy occurrence year. All localities should pay more attention to the prevention and control of diseases and pests in orchards in autumn and winter, pay close attention to the implementation of key measures, and lay a good foundation for reducing the occurrence degree of next year and ensuring high quality and high yield of fruit trees.
1 Occurrence
Judging by the number of adult worms. According to the monitoring in recent years, the fruit fly pests found in the orchards of our province are citrus small fruit fly, South Asian fruit fly, melon fly and so on. Among them, citrus fruit fly and South Asian fruit fly are the most harmful. Since September in southern Jiangsu Province, the insect attractances of citrus flies were significantly higher than that of the same period last year, and the cumulative insect attractances of individual orchards with severe cases were 10 times that of the same period last year. The insect quantity of South Asian fruit flies was higher in pear orchard, and the cumulative insect quantity of 782 flies per bottle since September 1 was higher than that of the same period last year by 9%. 410 head/bottle in Tongshan District, the same as the same period of last year; Suining County 59.7 head/bottle, 2.2 times that of the same period of last year, in peaches, grapes and other crops on the cumulative lure of insects in 0 ~ 74.6 head/bottle.
From the scope of occurrence. The incidence of citrus fruit fly gradually moved northward from the original southern area of Jiangsu Province, and was found in multiple monitoring sites in central and northern Jiangsu Province, involving 22 counties (cities and districts) in 8 districts of the province. South Asian fruit fly has a multi-point occurrence trend in all parts of the province, involving 31 counties (cities and districts) in 11 districts of the province.
From the hazard host. The results of a survey on the occurrence of citrus small flies in different fruit trees in Wujin District showed that since September 1, the highest total insect lure per bottle was 1,265 in pear orchard, followed by 235 in orange orchard and 220 in persimsima orchard. The cumulative insect population in peach orchard and pomegranate orchard was 146 head/bottle and 136.5 head/bottle. Some orchards in the late harvest period or the end of harvest had a large amount of insect fruit due to the reasons of excessive insect fruit, not timely clearing, lax control and so on. South Asian fruit fly not only harms fruit trees, but also a variety of melon vegetables such as luffa and cucumber.
2 Prevention and Control Technology
At present, the harvest of peaches, pears and other crops has basically ended, and citrus and other crops are in the harvest period. All localities should seize the key period of autumn and winter orchard pest prevention and control, increase the application of agricultural, physical, chemical and other prevention and control technologies, and effectively reduce the insect population base.
2.1 Agricultural Prevention and control
Once the worm fruit is found, it should be promptly removed, picked up and taken out of the garden for crushing, soaking or burning. After the end of harvesting, soil ploughing should be combined with autumn and winter fertilization, the ploughing depth is about 10 cm, so that the deep ploughing once and then the ramming rake once, killing the overwintering pupae in the soil layer. Do a good job of cleaning the winter garden, clean up the residual branches and leaves after winter shear, and use 3 to 5 beaum of stone sulfur mixture or mineral oil to clean the garden when the temperature is suitable.
2.2 Comprehensive trapping
One is the color plate trapping. Using the yellowing of fly pests, hanging yellow boards in orchards for trapping and killing, hanging 20 to 30 pieces per mu, hanging on the outside of the plant 2/3 height from the ground. The second is bait to kill. In view of the current mixed occurrence of various kinds of flies in orchards, the effect of food bait is better than that of sex bait. Orchards in the harvest period can use fly bait to apply or hang trap bottles.
2.3 Chemical Control
Orchards in the harvest period are not recommended to spray chemical agents directly. The harm can be reduced by adding abamectin, thiamethoxam and other agents to the attractant. In orchards that have been harvested, cypermethrin, avermectin, Metaria anisoplicans and other agents can be used for control to reduce the amount of overwintering insects.
Fruit fly pests in orchards are becoming heavier, and the prevention and control should not be relaxed in autumn and winter
2023 10/18