How to prevent and control white grubs when planting the Chinese medicinal herb Astragalus membranaceus
Astragalus membranaceus has a medicinal history of more than 2000 years. Due to long-term large-scale harvesting, the quantity of wild Astragalus membranaceus has sharply decreased in recent years, and there is a danger of it trending toward extinction. For this reason, this plant has been designated as a vulnerable species and a national third-class protected plant. Therefore, artificial cultivation of the Chinese medicinal herb Astragalus membranaceus is indispensable, but for growing Astragalus membranaceus, how to prevent and control white grubs is a headache-inducing problem.
White grubs are the larvae of scarab beetles, also known as white soil silkworms or walnut worms. The adults are collectively called scarab beetles or June beetles. They harm many kinds of plants and vegetables. According to their feeding habits, they can be divided into three categories: phytophagous, coprophagous, and saprophagous. Among them, phytophagous white grubs have a wide range of feeding habits and harm many crops, cash crops, and ornamental seedlings. They like to eat freshly sown seeds, roots, tubers, and seedlings. They are a worldwide underground pest with great harm.
White grubs occur severely in Astragalus membranaceus fields, and the white grub bodies are relatively large. The vertical activity habit of white grubs is mainly related to soil temperature. The optimum average soil temperature for their activity in the crop plow layer is 13°C-18°C. From late October to early November, when the soil temperature continues to drop, they burrow down into the 30-50 cm soil layer to make earthen cells and overwinter.
Control methods:
1. Agricultural measures.
Combining deep plowing and fine harrowing, crop rotation, and intertillage weeding and other measures can kill large numbers of white grubs in the soil.
2. Manual control.
During spring plowing and autumn plowing each year, pick up white grubs along with the plow, and they can be used as poultry feed.
3. Chemical control.
Because white grubs live in the soil throughout their lives, the key to chemical control is that the pesticide must be applied into the soil to achieve a relatively good control effect.
(1) Seed dressing with pesticide: This is the most economical, simple, and effective method for controlling white grubs. Commonly used pesticides include phoxim, chlorpyrifos, and others. Weigh the pesticide at 0.2% of the seed weight, add an appropriate amount of water to dilute it, mix evenly with the seeds, pile them up and let them sit for half a day, then sow.
(2) Soil pesticide treatment: Before sowing crops, use 300-500 grams of 15% phoxim-chlorpyrifos granules per mu, mix with soil, and evenly broadcast on the surface, then turn and mix into the plow layer soil. Or use 500 grams of 50% phoxim emulsifiable concentrate per mu, dilute with water, mix evenly with 50 kg of fine sandy soil, spread on the surface, turn and mix into the soil, and then sow.
(3) Toxic sand treatment of sowing furrows: Use 500 grams of 50% phoxim emulsifiable concentrate per mu, dilute with an appropriate amount of water, mix evenly with 20 kg of fine sandy soil, and apply into the sowing furrow, then sow. Or use 4-5 kg of 10% mecroprop granules per mu, open the furrow, spread the pesticide, cover with soil, sow, and then cover with soil again.
The above is relevant content on how to prevent and control white grubs in the Chinese medicinal herb Astragalus membranaceus. However, it is worth mentioning that although white grubs are a pest for growing Astragalus membranaceus, white grubs themselves can also be used as a Chinese medicinal material. According to records in relevant medical classics, white grubs have the effects of breaking blood, moving stasis, dissipating nodules, and promoting lactation, and are used to treat traumatic blood stasis pain, gout, tetanus, throat paralysis, eye opacity, erysipelas, carbuncles and abscesses, and hemorrhoids and fistulas. However, white grubs themselves have a certain toxicity, and only some varieties are used medicinally, so everyone must absolutely not take them on their own.