Key Technical Points for Pre-Winter Weed Control in Wheat Fields
Pre-Winter Weed Control Techniques in Wheat Fields
With changes in cropping systems and the influence of climatic factors, the weed community in wheat fields has undergone considerable changes. The variety of malignant grass weeds in wheat fields has been continuously increasing, and their range of occurrence has been continuously expanding. They compete with wheat for fertilizer, water, light, and space, causing poor individual development of wheat, a smaller population structure, and reduced uniformity of wheat in the field, which lowers wheat yield and quality and seriously affects wheat production. The affected area in our county has reached more than 20,000 mu, of which Bromus japonicus accounts for more than 13,000 mu, with an average density of 5.5 plants per sq m and a maximum density of more than 200 plants. All townships in the county have occurrences to varying degrees, mainly concentrated in Gaoling Township, Zhonghanzhuang Township, and Gudian Township. The peak period for weed emergence in the field is generally mostly before winter. Pre-winter weeds are small and easy to control, so pre-winter weed control in wheat fields is the key period for weed control.
1. Correctly select suitable herbicides.
(1) Control of broadleaf weeds. In our county, broadleaf weeds such as Descurainia sophia, shepherd's purse, and Silene conoidea are predominant. Pesticides such as tribenuron-methyl, thifensulfuron-methyl, bensulfuron-methyl, and isoproturon can be selected. Use 10 g-15 g of bensulfuron-methyl-type products per mu, spray evenly with 30 kg of water, or choose 2,4-D butyl ester.
(2) Control of grass weeds. For wheat fields mainly infested with Bromus japonicus, use Sigma, Puma, or BroadSigma for control; for wheat fields mainly infested with jointed goatgrass, use Sigma for control; for wheat fields mainly infested with shortawn foxtail, wild oat, and other grass weeds, use Puma. Use 20-35 ml of 3% Sigma oil suspension concentrate per mu (or 3 g of Puma per mu), dilute with 30 kg of water and spray. When mixing the pesticide, first use a small amount of water to make a mother liquid, then add water according to the dilution ratio, stir thoroughly, and spray evenly.
(3) For wheat fields with more Galium aparine and Asperugo procumbens, use combinations such as Mailao or Kuaimieling + Maikelong for tank-mixed spraying. Use 4-5 g of 40% Kuaimieling + 5 g of 18% Yili or 30-40 g of Mailao per mu, or 2 g of 40% Kuaimieling + 8 g of 10% Maikelong, mixed with 30 kg of water for foliar spraying.
(4) For fields with mixed infestation of grass weeds and broadleaf weeds, tank-mix tribenuron-methyl or bensulfuron-methyl with Puma or Sigma.
2. Several issues to note during control:
(1) Timing of weed control. Generally, it should be carried out one month after sowing winter wheat; in our county, this is mid-November, when wheat has 3-4 leaves and weeds have 2-3 leaves. Generally, the temperature should not be lower than 10 degrees.
(2) Scientific tank mixing. When spraying various herbicides, do not mix with organophosphorus pesticides without experimental verification, to avoid phytotoxicity. Puma should not be mixed with other grass herbicides.
(3) Safe application. Strictly control the dosage, application timing, and water volume, and spray evenly and thoroughly.
(4) Choose suitable weather. Herbicides should not be used in severe weather.
(5) After application, thoroughly clean the spraying equipment to avoid phytotoxicity to other crops.
(6) For plots with poor chemical weed control results, carry out manual pulling.
(7) Because 2,4-D butyl ester is sensitive to dicotyledonous crops such as cotton, vegetables, and fruit trees. After using this pesticide, spraying equipment with residual pesticide that is then used on cotton and other crops often causes phytotoxicity, so dedicated equipment is needed. Therefore, in wheat fields in cotton and peanut areas, try not to use 2,4-D butyl ester. Especially in spring, attention should be paid to accidents of phytotoxicity to dicotyledonous plants such as cotton, peanuts, and fruit trees.
1. Correctly select suitable herbicides.
(1) Control of broadleaf weeds. In our county, broadleaf weeds such as Descurainia sophia, shepherd's purse, and Silene conoidea are predominant. Pesticides such as tribenuron-methyl, thifensulfuron-methyl, bensulfuron-methyl, and isoproturon can be selected. Use 10 g-15 g of bensulfuron-methyl-type products per mu, spray evenly with 30 kg of water, or choose 2,4-D butyl ester.
(2) Control of grass weeds. For wheat fields mainly infested with Bromus japonicus, use Sigma, Puma, or BroadSigma for control; for wheat fields mainly infested with jointed goatgrass, use Sigma for control; for wheat fields mainly infested with shortawn foxtail, wild oat, and other grass weeds, use Puma. Use 20-35 ml of 3% Sigma oil suspension concentrate per mu (or 3 g of Puma per mu), dilute with 30 kg of water and spray. When mixing the pesticide, first use a small amount of water to make a mother liquid, then add water according to the dilution ratio, stir thoroughly, and spray evenly.
(3) For wheat fields with more Galium aparine and Asperugo procumbens, use combinations such as Mailao or Kuaimieling + Maikelong for tank-mixed spraying. Use 4-5 g of 40% Kuaimieling + 5 g of 18% Yili or 30-40 g of Mailao per mu, or 2 g of 40% Kuaimieling + 8 g of 10% Maikelong, mixed with 30 kg of water for foliar spraying.
(4) For fields with mixed infestation of grass weeds and broadleaf weeds, tank-mix tribenuron-methyl or bensulfuron-methyl with Puma or Sigma.
2. Several issues to note during control:
(1) Timing of weed control. Generally, it should be carried out one month after sowing winter wheat; in our county, this is mid-November, when wheat has 3-4 leaves and weeds have 2-3 leaves. Generally, the temperature should not be lower than 10 degrees.
(2) Scientific tank mixing. When spraying various herbicides, do not mix with organophosphorus pesticides without experimental verification, to avoid phytotoxicity. Puma should not be mixed with other grass herbicides.
(3) Safe application. Strictly control the dosage, application timing, and water volume, and spray evenly and thoroughly.
(4) Choose suitable weather. Herbicides should not be used in severe weather.
(5) After application, thoroughly clean the spraying equipment to avoid phytotoxicity to other crops.
(6) For plots with poor chemical weed control results, carry out manual pulling.
(7) Because 2,4-D butyl ester is sensitive to dicotyledonous crops such as cotton, vegetables, and fruit trees. After using this pesticide, spraying equipment with residual pesticide that is then used on cotton and other crops often causes phytotoxicity, so dedicated equipment is needed. Therefore, in wheat fields in cotton and peanut areas, try not to use 2,4-D butyl ester. Especially in spring, attention should be paid to accidents of phytotoxicity to dicotyledonous plants such as cotton, peanuts, and fruit trees.