The Sycamore tree suddenly dropped its leaves, indicating that it was infected by diseases and insect pests.

Soot disease, fruit rot, chafers, scale insects, venomous moths, aphids, fruit flies, debt avoidance moths, thrips, and gall mosquitoes are common in rose fruits. However, due to the long fruiting period of rose fruits and the peel Thin, so not suitable for pesticides.

Soot disease

Symptoms

The black sooty fungus forms a black covering on the surface of sycamore leaves, affecting the photosynthesis of the leaves. When the disease is severe, the growth of Sycamore is inhibited and it is difficult to extract flower buds or new buds. The fungus forms a black film on the leaf surface, which hinders photosynthesis of the leaves.

Pattern of incidence

Soot disease often occurs in orchards with poor management, especially when pest control is not effective. Sycamore pests such as leafhoppers, scale insects and whiteflies can secrete honeydew on the leaves or branches of Sycamore, causing sooty disease. The occurrence of sooty disease is caused by insects. When the density of harmful insects is high, the occurrence of sooty disease will also be serious.

Prevention and treatment methods

Mainly focus on preventing and controlling pests. Controlling the growth and decline of pests can control the occurrence of this disease. Once fruit trees in the field are damaged by soot disease, the affected leaves and branches can be cut off to reduce the source of infection. In addition, in orchards where sooty disease is serious, foliar spraying of nutrients containing carbohydrates (such as sugar, etc.) should be reduced or avoided as much as possible.

Fruit rot

Symptoms

Fruit rot pathogens attack the leaves and fruits of rose apples. The fruit is severely damaged, with water-soaked, faded spots or lavender spots forming in the early stages of the disease. The lesions expand into a round shape, with piles of conidia scattered on the surface, which appear as small black dot-like protrusions. The color of the flesh becomes lighter, with yellowish brown or lavender spots appearing, and finally turns into dark purple or black. The diseased fruit often hangs on the branches and does not fall to the ground immediately. In the later stage, the fruit dehydrates, shrinks and withers, and falls to the ground in a dry shape. Irregular brown lesions form on the affected leaves, and later black dots appear scattered on the surface of the lesions.

Prevention and Control Methods

Chemical agents available for prevention and control include zinc, ethyl aluminum, retinosporin, etc.

Physical control uses bagging to block the invasion of germs.

Spray the hosts in the garden at the same time to reduce the occurrence of pathogens and diseases.

Clean orchards to avoid spreading infection.

Algae spot disease

Symptoms

Two different forms of lesions can be formed on the leaves: one has fine hairs on the surface, which are the sporangia of the pathogen The stalk and terminal spores are sporulated, and the periphery of the lesions is transparent and oily. Injured rose apple leaves will fall off early, affecting photosynthesis and thus affecting the quality of the apple.

Control methods

Cultivation management and chemical methods can be used to reduce the pathogen. For example, strong heat pruning, chemicals or fertilizers force the leaves to fall, reducing the pathogen to a minimum. Proper pruning during the growth process to ensure good ventilation of the branches can effectively reduce algae spot disease. Organic copper agents or Bordeaux mixture have a very good inhibitory effect on algal spot pathogens.

Oriental fruit fly

Symptoms

The female lays eggs on the surface of the fruit, and the larvae eat the fruit, causing the nearby fruit pulp to rot and causing fruit drop. Mature larvae emerge from the fruit pulp and pupate in the ground. Adult insects can lay up to 1,000 eggs. One generation in the high temperature period is shorter than 1 month, and reproduction is rapid.

Control methods

During the fruiting period, toxic methyl clove oil, insect trap lamps or fiberboards can be hung to attract and eliminate male insects. This method only attracts and eliminates male insects and is ineffective against female insects. Nearby fruits need to be hung at the same time, otherwise the effect will not be very good.

Chemical control. You can spread 25% Marathon wettable powder, or 5% fenthion emulsion 200 times mixed with protein hydrolyzate (or 3% brown sugar water), spray once every 7 days, spray on small trees and the crown, near the orchard Spray the leaves of grass or trees to kill adult insects.

Clean the orchard, pick up diseased and rotten fruits and bury them deep in the soil or flood them.

Bagging. Bagging can be used to prevent fruit flies, birds and cold damage.