2,4-DB was first registered in alfalfa fields

Recently, 30% of 2, 4-DB products (with 33% Sodium salt content of 2, 4-DB) of CYNDA were approved to be extended for registration. The newly registered crops and control objects are annual broadleaf weeds and sedge weeds in alfalfa field. It is recommended to use 150-200 ml formulation mixed with 25 ~ 30 kg of water per mu at the 2~5 leaf stage of weeds, or according to the actual local agricultural production mixed with even spray water, at most 1 time per season. This is the first time that 2, 4-DB has been registered in alfalfa fields.

2, 4-DB is an analogue of 2, 4-D and acts in a different way than common hormone herbicides. It has no biological activity and is oxidized to 2, 4-D by β-oxidase after absorption. In alfalfa, corn and paddy, 2, 4-DB cannot be metabolized due to the low activity of β-oxidase, showing high safety for these crops.

In our history, two Imazethapyr products were approved for temporary registration to control annual weeds in alfalfa field, but the two temporary registration certificates for pesticides expired in 2008. Syngenta's 200g/L Paraquat AS was officially registered in China to control leguminous grass (including alfalfa) weeds, but it has been eliminated. In 1986, China approved the official registration of four 25% Bentazone As, which are still in effective state. The registered crops and control objects include grassland and pasture broad-leaved weeds.

 The experimental results of Plant Protection College of Agricultural University of Hebei and other units showed that 33% Pendimethalin EC and 48% Trifluralin EC were safe for alfalfa growth in 10 soil treated herbicides tested at the recommended and doubled dose levels. Among the 14 stem and leaf treatment herbicides tested, 10% Quizalofop-p-ethyl EC and double dose were safe for alfalfa growth, 15% Clodinafop-propargyl EW was safe for alfalfa growth at recommended dose, but had inhibitory effect at double dose. 

The experimental results of Plant Protection Institute of Shandong Academy of Agricultural Sciences showed that Imazapic can be used to control grass or broad-leaved weeds in alfalfa field, and it has good safety and weed control effect on alfalfa field.

The Haloxyfop-P, Quizalofop-p-ethyl and Clethodim can be used in alfalfa fields dominated by gramineous weeds. Alfalfa field dominated by broad-leaved weeds can be used in alfalfa field, which is safe for alfalfa and has good control effect on broad-leaved weeds, but has poor or ineffective control effect on gramineous weeds. The Plant Protection Institute of Henan Academy of Agricultural Sciences and other units also showed that the dose treatment of Imazapic of 86.4 ~ 100.8 g/hm2 has a good control effect on weeds, has no adverse effects on the growth and quality of alfalfa and can significantly improve the yield, which has a good application value in production.

Alfalfa is an important forage which is mainly used for livestock feeding. Because of its high economic benefits, its production and sales have become an industry. Alfalfa is prolific and high quality, which can provide continuous power for the sustainable development of animal husbandry. According to statistics, by 2020, alfalfa planting area reached 6.5 million mu, the output of 3.4 million tons. However, domestic alfalfa accounts for only about 24% of alfalfa consumption in breeding farms, and the rest are imported alfalfa. It is proposed to vigorously promote the construction of alfalfa industrial belts in Northwest, North China, Northeast and part of Central Plains, build a batch of high quality and high yield alfalfa commercial grass bases, gradually realize the local supply of high quality alfalfa and ensure the demand for large-scale dairy farming alfalfa.