1. Weedy rice

It is rice companion weed, with two growth habits of uncultivated and cultivated. And it has high adaptation, vigorous growth, high ear bearing tiller rate, high grains per panicle, high propagation coefficient. Meanwhile, it is hard to distinguish, remove, prevent and kill off.

2. Barnyard grass

Barnyard grass and rice are very similar in appearance, stems erect, base inclined or geniculate, smooth glabrous, leaf sheath loose, no leaf tongue, leaf blade glabrous, Inflorescence spindle angular, coarse, spikelets densely on one side of cob, with very short stalks or subsessile. Compared with rice, the blade of barnyard grass is more hairy and astringent, and the color is lighter.

3.Alternanthera philoxeroides

The scientific name of alternanthera philoxeroides is the hollow lotus seed grass, perennial herb. Stem tubular with inconspicuous 4 ribs, base prostrate, upper ascending, branching, young stem and leaf axils with white or rust-colored pilose, stem glabrous when old. Leaf blade rounded, rounded obovate or obovate lanceolate.

4.Nutgrass flatsedge

Nutgrass flatsedge has two propagation modes, sexual and asexual, with many propagation routes, especially the propagation of underground deep roots and corms. There are many kinds of sedge in paddy field and they can compound and overlap. Due to the staggered growth period, it is difficult to timely use the medicine for each species. Meanwhile, the stem of the sedge is upright and knobless and smooth, and the herbicide is difficult to stick and penetrate, lacking effective control measures. The common types in the paddy field were broken rice sedge, heteromous sedge, aconite and currant.

5.Lecrsia oryzoides

It is commonly known as "wandering grass" of rice. It can reproduce bisexual through seeds and creeping roots. Each plant can produce 8 ~ 14 tillers and 150 ~ 250 seeds per panicle. The underground rhizome has 7 ~ 8 bud nodes, all of which can form new plants with strong feculence. Developed roots, strong vitality, vigorous growth, plant height up to 90 ~ 120 cm, less special herbicides in production.

6.Sagittaria trifolia

Sagittaria trifolia with rhizome, stem stout, terminal expansion or not. The length and width of the leaves vary greatly. Sagittaria trifolia can be bisexual propagation, especially to the underground thick hengsheng stem strong vitality, seedling depth up to 15 cm. At the same time, its strong cold resistance, minus 5 ~ 6 still maintain vitality, plant tall strong drug resistance, production is difficult to control.

7.Leptochloa chinensis

Due to the continuous use of rice direct-seeding technology and the long-term use of a single herbicide, the population of leptochloa chinensis rapidly in the paddy fields in recent years. Stem upper upright, smooth glabrous. Leaf blade lanceolate, glabrous. Because leptochloa chinensis clumps and softer stems and leaves, the breeze in the rice field is a bright, easy to distinguish.

8.Digitaria sanguinalis

Digitaria sanguinalis is a common malignant weed in the dry direct rice field, its stem is upright or its lower part is inclined, and it is hairless or pubescent. Leaf blade lanceolate, base rounded, margin thicker, slightly coarse, pilose or glabrous.

9.Ludwigia prostrata

An erect annual herb of Ludwigia prostrata, lower stem terete, upper quadrigonal, often reddish. Leaves narrowly elliptic, apex acute or slightly obtuse, base narrowly cuneate, abruptly narrowed at lower part.

10.Ammannia auriculata

Amaranthus auricularis is an annual herb, the stem has 4 edges, often many branches. Leaves opposite, sessile, leaves base halberd long narrow auriculate.