At the initial stage of the disease, the white powdery round spots appeared on the back of the leaves, and then gradually expanded into pieces, while the front color of the mulberry leaves became light yellow brown; at the later stage, in the center of these spots, dense yellow small dots, and then turned black. The disease mainly occurs in the leaves in the middle of branches, early hardening varieties, etc. The main control methods are as follows:
1. Sericulture in batches in autumn, first picking the mulberry leaves under the mulberry strips;
2. Drought resistance in time in dry season to delay the hardening of mulberry leaves;
3. Spray the leaves with a 1000 fold solution of 50% tobramycin at the beginning of the disease, and spray again every 10-15 days.
Most of them occur in young leaves, especially in the hot, humid and sunshine deficient weather. At the initial stage, it is water stained sesame granular disease spot, which is dark brown in color, and then expands to near round or irregular disease spot. White or reddish powder blocks are formed around the disease spot, and then the color becomes black brown, and the leaf color slightly turns yellow. In serious cases, the disease spots are connected with each other, and the leaves are easy to fall off when they are dry and yellow. The main control measures are as follows:
In the early stage of the disease, spraying the leaves with 50% carbendazim 1500 times solution or 75% methyltobramycin 1500 times solution can achieve better control effect, and there is no harm to silkworms.
There are many kinds, mainly including black velvet scarab, brown scarab, and bronze scarab. It is harmful for adults to eat mulberry buds, young shoots and mulberry leaves, especially for seedlings. The control methods are as follows:
1. Use the feign death of the beetle to catch and kill the adult in the evening.
2. Light traps adults.
3. When ploughing in winter, the grubs of larva and seedling root should be removed with plough.
4. In the evening, spray 1000 times 80% dichlorvos emulsion or 1000 times 50% phoxim emulsion to kill the adults.
