Focus on biological measures to prevent apple caterpillars

Grape and apple varieties that farmers in the South Central region love

Apple is a tropical fruit tree, drought-resistant, can be grown in many different ecological zones, can grow in areas with harsh natural conditions, especially in hot and dry areas, with high temperature amplitude, the quality of the fruit is more delicious, sweet, crispy.

People's apple orchards are damaged by caterpillars. Photo: PC

With these characteristics, in recent years, green apples have been grown in the South Central provinces such as Ninh Thuan, Binh Thuan, Khanh Hoa with an area of ​​about 1,450 hectares, of which the largest is Ninh Thuan province with thousands of hectares. Apples can be harvested all year round with a yield of 40 - 50 tons/ha/year, each year people have an income of 500 - 700 million VND/ha.

According to Dr. Phan Cong Kien, Deputy Director of Nha Ho Cotton Research and Agricultural Development Institute (Nha Ho Institute), apple is an easy-to-grow tree, can be harvested for many years after planting, has high economic value, and helps people in the area get rich. However, in recent years, caterpillars have appeared and caused quite a lot of damage in some apple growing areas in the localities, reducing productivity and fruit quality.

“Through monitoring and field surveys by the Nha Ho Institute, it is shown that when people use anti-fruit fly nets to harm apples, caterpillars tend to appear more frequently, with greater ability to spread and affect apple trees and fruits. This is a new species that has appeared and caused local damage, so there is no synchronous management process, people have to use a lot of pesticides, which affects the quality of apples,” said Dr. Phan Cong Kien.

According to Dr. Kien, caterpillars are omnivorous and cause damage to many plants, including apple trees. Caterpillars often cause damage to fruit, leaves, young shoots, and old leaves. They often form cocoons to raise pupae, waiting for the day to transform into butterflies to continue their life cycle. If not detected and managed promptly, apple trees can be completely eaten by caterpillars, including the trunk, fruit, and leaves.

Caterpillars eat very well and reproduce quickly. In a newly hatched nest, there can be up to a thousand worms and in just one night, they can eat all the leaves, buds and young fruits. During the flowering and young fruit stage, if caterpillars appear and attack without effective control, it will greatly affect the yield and quality of the fruit.

The caterpillars are characterized by lying under the leaves and rarely moving. They crawl out in the early morning or late afternoon to destroy one branch after another. In sunny weather, they crawl down the trunk or hide under the leaves, making them difficult to detect. This type of worm appears most often during the changing seasons. Although it does not kill the tree like other diseases, the worms attack all the young shoots, young leaves and young fruits, significantly affecting the growth process, yield and quality of apples.

Dr. Phan Cong Kien said that to effectively manage apple caterpillars, people should apply a series of measures such as: creating a canopy, pruning branches for an airy apple orchard, regularly pruning off branches, diseased branches, and old branches inside the tree trunk that are not capable of producing fruit.

Along with that, regularly visit the garden, check, detect pests and diseases in time and use manual methods to destroy pupae, eggs and larvae of caterpillars. People should collect branches and leaves with eggs and newly hatched larvae and take them outside to destroy them. This is a very effective measure because each nest of young caterpillars can contain up to thousands of larvae.

At the same time, trap adult caterpillars with biological light traps. This method can combine two luring methods (luring from a distance with high intensity pale yellow light and luring nearby with purple light, UV rays with a wavelength of 300 - 380nm). For light traps, it can be combined with sticky traps or a basin of water with mineral oil poured on top to collect adults when they gather at the light trap.

In addition to the above measures to prevent caterpillars, in case it is necessary to use chemicals, early detection is very important because when the caterpillars are older, they will disperse and cause harm to the apple tree. Therefore, early detection for prevention will be highly effective. People use the medicine according to the manufacturer's recommended dosage, and should combine it with mineral oil or adhesives to increase the effectiveness of the medicine. The time to spray the medicine at the larval stage from age 1 to age 3 is most effective because at this stage the larvae live concentrated on the canopy, move slowly and have poor endurance.

Huong Hoai (According to nongnghiep.vn)

Source: http://baovinhphuc.com.vn/Multimedia/Images/Id/126707/Chu-trong-bien-phap-sinh-hoc-phong-tru-sau-rom-hai-tao