Identification and Control Methods for Leafminer Fly Infestation on Snake Gourd

Snake gourd is an annual climbing vine; the stem is slender, much branched, with longitudinal ridges and grooves, covered with short soft hairs and sparsely with long hirsute hairs. The snake gourd root system is well developed, with many lateral roots and prone to producing adventitious roots. The stems and vines are slender and long, reaching 5-8 m in length. The stem is five-angled and green, with strong branching ability, and the leaves are green, palmately deeply lobed, with relatively rounded sinuses and fine down on the leaf surface. The corolla is white, and the flowers are unisexual, with male and female flowers similarly differentiated. Male flowers are mostly in racemes, green in the bud stage and pale yellow-green when about to open. Male flowers appear earlier than female flowers. Generally, female flowers begin to form at the 20th-25th nodes of the main vine, after which both the main vine and lateral vines can continuously produce female flowers.

The snake gourd has several green lines starting from the fruit stalk. Some fruits hang vertically, some are arched, some curved, and some have curled tails, closely resembling one long snake after another posing under the trellis. In the young fruit stage, the fruit surface has alternating white and green stripes like a white-banded snake. After maturity, the fruit surface shows alternating red and green stripes like a red-banded snake, with varied postures, vivid and lifelike, strange yet beautiful. If cultivated properly, each plant can bear more than 0 fruits. Looking up, snake-like long gourds hang down from the trellis, full of southern charm, with high ornamental value, making it a rare good variety for developing sightseeing agriculture.

Every 100 g of young snake gourd fruit contains 94-95 g water, 0.5-0.9 g protein, 0.1 g fat, 0.8 g crude fiber, 3-4 g carbohydrates, and also contains mineral salts and various other nutrients. Snake gourd clears summer heat and relieves fever, promotes urination and lowers blood pressure, and is very beneficial to human health. The young fruit is rich in carbohydrates, vitamins and minerals. The flesh is soft and has a slight unpleasant odor, but after cooking it becomes fragrant and slightly sweet. Snake gourd is eaten as a vegetable mainly in its young fruit stage, but the young leaves and young stems are also edible. Every 1 kg of young snake gourd fruit contains 5-9 g protein, 30-40 g carbohydrates, and other nutrients.

Introduction and control of the snake gourd pest leafminer fly

What is a leafminer fly?

Leafminer flies belong to the Diptera order of flies and are leafminer pests that mainly damage lawns. Common ones in China include the pea leafminer and milk vetch leafminer in the Agromyzidae family, the rice leafminer in the Ephydridae family, and the beet leafminer in the Anthomyiidae family. They have lapping-sponging mouthparts and damage plant leaves as larvae. The larvae often bore into leaf tissues and mine the mesophyll tissue, causing irregular white stripes on the leaves, gradually turning the leaves yellow and withered, causing chlorophyll decomposition in the leaves and reducing sugar content in the leaves. When the damage is severe, the affected plants' leaves turn yellow and fall off, and even the seedlings die.

Damage symptoms of the snake gourd pest leafminer fly:

The larvae burrow under the epidermis of the host leaves, winding through and feeding on green tissue, creating irregular grayish-white linear tunnels. When the damage is severe, almost all leaf tissue is affected, and the leaves are covered with mines, especially the leaves at the base of the plant, which suffer the most and may even wither and die. The larvae can also mine young pods and flower stalks. Adults can also suck plant sap, leaving small white spots at the feeding sites.

Control methods for the snake gourd pest leafminer fly:

1. Irrigate at the proper time, remove weeds, eliminate overwintering and oversummering sources of the pest, and reduce the insect population base.

2. Grasp the peak emergence period of adults, spray pesticide in time to control adults, and prevent adults from laying eggs. Adults mainly lay eggs on the underside of leaves, so pesticide should be sprayed on the underside of leaves. Or spray pesticide to control larvae when damage first appears. For larval control, spray 2-3 times continuously. Pesticides may include 40% dimethoate emulsifiable concentrate 1000x dilution, 40% omethoate emulsifiable concentrate 1000-2000x dilution, 50% dichlorvos emulsifiable concentrate 800x dilution, 50% naled emulsifiable concentrate 1500x dilution, and 40% diazinon emulsifiable concentrate 1000-1500x dilution.