Pear-lime moths, commonly known as "stratum worms" by fruit farmers, are a minor but persistent threat to fruit trees. While they typically cause only slight damage, severe infestations can lead to the decline or even death of pear trees. Understanding their life cycle and symptoms is crucial for effective management.
**Life Cycle and Symptoms:**
These pests have two generations per year. The first generation consists of one-year-old larvae that overwinter inside damaged twig tunnels. As spring approaches, usually in late March, these larvae become active, feeding on the sap of branches. The tunnels created by the first-instar larvae are very narrow, but as the larvae grow, the tunnels gradually expand. By the fifth instar, the tunnels merge into a single, thickened sheet. At this stage, the larvae stop expanding the tunnels and instead move to the skin or the lower layers of the pear fruit, feeding on it. This feeding activity causes the affected areas to form multiple layers of dry, paper-like skin, which eventually split from one side, leading to shriveling and tilting of the fruit.
**Prevention and Control Measures:**
1. **Timing of Control:**
The best time to implement control measures is from December to early March, before the pear buds begin to open. This period is critical for targeting overwintering larvae.
2. **Control Methods:**
(1) **Manual Removal:**
During winter pruning, farmers can cut off and remove any damaged branches. These should be collected in one area and burned to eliminate the overwintering pest population.
(2) **Chemical Control:**
During the adult moth emergence period, spraying with a 50% parathion solution diluted at 2000 times or dichlorvos at 1000–1500 times concentration is recommended. Two to three applications, spaced about a month apart, can effectively reduce the population. Additionally, during the larval tunneling phase, direct application of parathion into the tunnels can help kill the larvae.
(3) **Methyl Bromide Fumigation:**
When propagating new seedlings, they can be placed in a controlled room maintained at 8–9°C. Methyl bromide is applied at a rate of 45 grams per cubic meter and sealed for six hours. This method has proven to be 100% effective against larvae without harming the seedlings.
By combining these methods, farmers can significantly reduce the impact of pear-lime moths and protect their crops from long-term damage. Regular monitoring and timely intervention are key to successful pest management.
Herbal Extract,Blood Lipid Reduction,Natural Supplements
Youth Biotech CO,. Ltd. , https://www.youtherb.com