Experience and Technical Key Points in Grasshopper Rearing and Management

1) Biological Characteristics of Grasshoppers

Grasshoppers are insects used both as medicine and food. They are oviparous and belong to the class Insecta, order Orthoptera, family Acrididae. According to statistics, the family Acrididae contains a total of 859 species of grasshoppers, but only two can be used medicinally and for food, namely the East Asian migratory locust grasshopper and the rice migratory locust grasshopper. Grasshoppers are rich in protein, carbohydrates, insect hormones and other active substances, and also contain vitamins A, B, C and elements such as phosphorus, calcium, iron, zinc and manganese. Grasshoppers are not only a delicious delicacy, but also a good medicine for treating diseases. Used alone or in combination, grasshoppers can treat many diseases, such as tetanus, infantile convulsions, fever, and asthma. Grasshoppers are dioecious, mate naturally, and are oviparous. Under natural conditions, they reproduce 2 generations per year, namely the summer locust and the autumn locust.

2) Construction of Grasshopper Rearing Sheds

The rearing shed should be built in a ventilated, sunny place. The ground of the shed should be about 10 cm higher than the surrounding ground to facilitate drainage. The soil is best if it is sandy loam, which makes it easy to collect grasshopper eggs. On the ground of the rearing shed, monocotyledonous plants such as wheat or corn should be planted to provide food for the grasshoppers. The construction area should be determined according to the number of grasshoppers; about 15 sq m is needed for every 10,000 grasshoppers. Use angle iron, wooden sticks and the like to build the shed frame, then according to the size of the shed, use gauze netting as the shed cover, bury the bottom edge underground, and leave a doorway. A zipper is installed on the doorway to prevent the grasshoppers from escaping and to allow people to enter and leave the shed. The shed height should preferably be 1.5-2 m. To keep warm and prevent rain, the outside of the shed can be covered with plastic sheeting. When rearing grasshoppers under natural conditions, the construction of the shed must be completed before the end of April.

3) Rearing and Management of Grasshoppers

The suitable development temperature for grasshoppers is 25-32°C, the relative humidity is 85%-92%, and the soil moisture content is 15%-18%. Below 14°C or above 40°C, grasshoppers gradually stop feeding and die. When the temperature reaches 28-30°C, grasshopper eggs begin to hatch. First prepare non-toxic soil and sawdust powder and mix them at 1:2, with a moisture content of 20%-30%. Spread 3-5 cm of soil in a container and pat it firm, then distribute the grasshopper eggs on the soil, and cover with about 1 cm of the mixed soil. Finally, cover the container with a layer of film, and check once every half day. After finding small grasshoppers, use a soft brush to brush them onto the food in the shed. After 10-15 days, small grasshoppers hatch out. Newly emerged small grasshoppers like to eat fresh and tender wheat seedlings, corn seedlings, weeds and other monocotyledonous plants, but their food intake is very small. Grasshoppers at the 1st-3rd instars should be protected from rain. From emergence to adult takes about 27-35 days. During this period, they molt once every 5-7 days, for a total of 5 molts; after the 5th instar, grasshoppers gradually begin to mate and lay eggs, and each grasshopper lays about 70-100 eggs. In order to feed and lay eggs for reproduction, grasshoppers are fond of living in groups and migrating. Therefore, after eclosion and before egg laying, appropriate disturbance should be given to make them migrate, so as to increase the number and quality of eggs laid. Before freezing, some wheat bran, weeds and the like should be added over the egg-laying area to keep warm and retain moisture, preventing the eggs from cracking due to freezing. Adult grasshoppers in the growing period should be sold in time if they are not to be kept for breeding.