1. Weedy rice

Deep tillage should be carried out before rice planting to inhibit germination of rice seeds left in the field. When a small amount of weedy rice grows in the field, attention should be paid to timely pull out at the seedling stage and heading stage to prevent a large number of miscellaneous rice seeds from being left in the field after maturity. The fields of water-direct rice were sealed with pretilachlor before the seedlings were planted. The planting time of weedy rice was postponed after the planting with glyphosate and paraquat. When the amount of weed rice is large, it is suggested to change to cotton, corn, or to do rice transplanting field, in time after the transplanting rice to green live plants with acetochlor, metolachlor and other drugs to do closed treatment.

2. Barnyard grass

The sensitivity of different barnyard grasses to different herbicides is different. For stem and leaf herbicides, the barnyard grass was used for 2 ~ 3 stages, and the best prevention effect for the five barnyard grasses tested were penoxsulam, Han Qiuhao, quinclorac, bispyribac-sodium, and propanil. At present, 10% fenoxaprop-p-ethyl/ cyhalofop-butyl EC has a good killing effect against resistant barnweeds.

3. Alternanthera philoxeroides

A variety of herbicides can be used to increase the amount of herbicides for control of empty stubble of rice. Small density can be manually removed. In the growing period of rice, glyphosate and glufosinate with spray cover can be used to spray the groundnut in the field, and glyphosate 90 ~ 120 g and glufosinate 80 ~ 100 g/mu can be used in the field, 20% fluroxypyr EC 80 ~ 110 mL/mu whole-field spray can be used in the field, which is the only agent that can effectively prevent alternanthera philoxeroides and is safe to rice at present. If necessary, ducks can be put out for biological control.

4. Nutgrass flatsedge

30% anilofos EC 60~80 mL/mu can be used in soil treatment. 56% MCPA-Na WP 60~80g/mu can be used for stem and leaf treatment, but the dosage should not be too large or the medication period should not be late. Using 48% bentazone AS 180~220mL/mu or 75% halosulfuron methyl WDG 6~10g /mu, it can penetrate into underground roots or bulbs, and kill them completely.

5. Lecrsia oryzoides

At present, only bispyribac-sodium and pyribenzoxim are effective agents for lecrsia oryzoides.The 10% bispyribac-sodium EC could be used for 100 ~ 200 g/mu, and it could be used according to the treatment method of rice stem and leaf before tiller of rice. At the same time pay attention to the root stubble in the field after ploughing to prevent rooting.

6. Sagittaria trifolia

Bentazone 48% SL 180 ~ 220 mL/mu, prometryn 50% WP 80 ~ 110 g/mu, simetryn 25% WP 180 ~ 220 g/mu, according to the stem and leaf herbicide use method when sagittaria trifolia at 8 ~ 10 cm, and pay attention to pick up the remaining underground stem when ploughing the land.

7. Leptochloa chinensis

At present, closed weeding is still the main technical measure for prevention and control of Leptochloa chinensis. Pretilachlor containing safener can be used before the emergence of Leptochloa chinensis. Penoxsulam, metamifop, bispyribac-sodium, pyribenzoxim, can be mixed with cyhalofop-butyl to prevent and remove the 2 ~ 3-leafed that has already grown. During application, field water is drained and sprayed evenly, and water is rehydrated in 2 ~ 3 days after treatment.

8. Digitaria sanguinalis

In Digitaria sanguinalis which appeared in the stage of one leaf of dry direct rice, cyhalofop-butyl and penoxsulam could be used for weeding. After two leaves of rice, cyhalofop-butyl can be added with quinclorac, fluroxypyr-meptyl. Three leaves can use metamifop, fiveleaves, it is recommended to use cyhalofop-buty and fenoxaprop-P-ethyl for weeding.

9. Ludwigia prostrata and Ammannia auriculata

Ludwigia prostrata and Ammannia auriculata are highly resistant to herbicides such as bensulfuron-methyl, pyrazosulfuron-ethyl, penoxsulam and so on. Herbicides such bentazone, 2-methyl-4 chloride and fluroxypyr-meptyl can be used for stem and leaf treatment, and oxadiazon, butachlor and pretilachlor can be used as closed weeding.