What are the key technical points for post-harvest pest and disease control in loquat?

Currently, most loquat fruit has been harvested. In addition to strengthening fertilizer and water management, pest and disease control is also an important prerequisite for ensuring whether the fruit trees can grow and develop normally and flower and bear fruit later. The main pests and diseases after loquat harvest include leaf spot disease, pear psylla, mites, aphids, etc. Combined with recent weather conditions, the occurrence characteristics of these pests and diseases and the key technical points for their control are introduced as follows.

1. Recent occurrence of pests and diseases 1. Loquat leaf spot disease: mainly manifested as gray spot, spot, angular leaf spot, and ring spot symptoms, and occurs severely in the rainy summer and autumn seasons. This disease not only damages leaves, causing them to turn yellow, wither, perforate, and fall off, but also affects new shoot growth, ultimately affecting photosynthesis. It generally occurs more severely from April to September. A recent survey found that in a few orchards with poor management, the disease was very severe, and 50% of the leaves had already fallen off. The occurrence of high temperature and rainy weather later is conducive to the occurrence of this disease, so the control of leaf spot disease cannot be ignored. 2. Pear psylla: In recent years, psylla has commonly occurred on loquat in our region, with multiple generations per year, and occurs more severely in dry seasons. After fruit harvest, its damage sites are mainly concentrated in the crevices at the base of the petiole, and it secretes mucus, giving it strong resistance to rain washing. In the summer and autumn of last year, pear psylla occurred relatively heavily on loquat, accumulating a large amount of insect sources; this year, affected by warm winter weather, with early drought and relatively high temperatures recently, it is conducive to the occurrence of psylla. Especially in orchards intercropped or relay-cropped with pear trees, the occurrence of pear psylla is more severe. In severely affected orchards, the rate of infested new shoots reached more than 80%. 3. Loquat nymph mites: nymph mites mainly damage new shoots and flower spikes and are a commonly occurring harmful mite on loquat in our region; recent surveys show that mite numbers are not high, but later high temperature and drought will make occurrence more severe. 4. Other pests: yellow caterpillars mainly damage new shoots and leaves, and aphids damage new shoots, so control should also be strengthened after fruit harvest.

2. Comprehensive control technical measures: 1. Agricultural measures: strengthen fertilizer and water management, avoid excessive dryness or excessive moisture, enhance tree vigor, improve disease resistance, remove fallen leaves in a timely manner, and, in combination with fertilization, appropriately plow the soil to reduce the base number of pest and disease sources. Minimize intercropping, mixed cropping, or relay cropping of pear trees and loquat trees. 2. Physical control: install insect-killing lamps in the field and use light to trap and kill adult pests such as psylla and yellow caterpillars; use yellow boards to trap and kill aphids. 3. Biological control: when the number of mites per leaf is below 2, predatory mites can be used to control various mites; at the same time, plant and retain grass to attract natural enemies and use their natural pest control ability to control outbreaks of pests, such as using seven-spot ladybirds to control aphids. 4. Chemical control: seize the key period and apply pesticides for control. When the average number of mites per leaf reaches 3-5, apply 34% Shamanxing at 2000-2500 times dilution, or 2.4% abamectin at 3000 times dilution, etc., to control nymph mites; to control psylla, apply pesticides during the young larval stage, and the pesticide can be 25% Actara at 8000 times dilution or 2.5% Mushi Jing for control. To control leaf spot disease, any one of the pesticides Shigao, Bobang, or Xinsheng can be selected for control.