Effects of four herbicides(paraquat, acetochlor, nicosulfuron and atrazine) on the growth of maize and control effect of plant quantity and fresh weight of weeds were studied. The results showed that 15 days after spr...Effects of four herbicides(paraquat, acetochlor, nicosulfuron and atrazine) on the growth of maize and control effect of plant quantity and fresh weight of weeds were studied. The results showed that 15 days after spraying the herbicides on weeds,the prevention and control effect of paraquat on weeds was the optimum, and its effects on the plant quantity and fresh weight of weeds were above 81.57%; the prevention and control effect of acetochlor on weeds was the second best; the prevention and control effect of atrazine on weeds was the worst, and its effects on the plant quantity and fresh weight of weeds were only 51.04% and 37.86%. After 30 or 45 days, the prevention and control effect of atrazine and nicosulfuron on weeds in the maize fields was better than the other herbicides, and their effects on the plant quantity and fresh weight of weeds were higher than 70.00% and 85.00%. Acetochlor and paraquat had certain phytotoxicity to the growth of maize after about 15 days, and its leaves became yellow and grew slowly. On the whole, nicosulfuron had good prevention and control effect on weeds and had no phytotoxicity to the growth of maize.展开更多
Trianthema portulacastrum L. （commonly known as horse purslane） is a noxious weed of several economically important field crops in tropical regions of the world. An intensive work on the screening of the biocontrol ...Trianthema portulacastrum L. （commonly known as horse purslane） is a noxious weed of several economically important field crops in tropical regions of the world. An intensive work on the screening of the biocontrol agents was accomplished through in vitro epidemic study to control weed populations. The foliar disease symptoms on infected weed plants caused by fungal pathogens represented as round to irregular maroon spots with dark borders and the epidemic was identified as leaf spot disease. The pathogen allied with the infection of horse purslane was isolated from infectious propagules by inoculation of leaf bites on a nutrient medium, potato dextrose agar （PDA）. The causal agent of leaf spot was confirmed as Gibbago trianthemae Simmons by Koch＇s postulates. The mycoherbicide ability of G. trianthemae has been examined through visual （standard area diagram） and statistical methods （analysis of variance using the Microsoft Office Excel-Data Analysis Tool Pack 2007）. The results revealed that the pathogen causes significantly （P 〈 0.05） severe infection on host weed and destructs the weed population by leaf spot diseases. The findings of the research suggested that the isolate G. trianthemae is highly virulent and host-specific, and recommended for further studies as a promising biocontrol agent against horse purslane weed.展开更多
基金Supported by Open Foundation for Key Laboratories of Education Department of Hunan Province(15K067)Key Laboratory of Pesticide Harmless Application of an University in Hunan Province
文摘Effects of four herbicides(paraquat, acetochlor, nicosulfuron and atrazine) on the growth of maize and control effect of plant quantity and fresh weight of weeds were studied. The results showed that 15 days after spraying the herbicides on weeds,the prevention and control effect of paraquat on weeds was the optimum, and its effects on the plant quantity and fresh weight of weeds were above 81.57%; the prevention and control effect of acetochlor on weeds was the second best; the prevention and control effect of atrazine on weeds was the worst, and its effects on the plant quantity and fresh weight of weeds were only 51.04% and 37.86%. After 30 or 45 days, the prevention and control effect of atrazine and nicosulfuron on weeds in the maize fields was better than the other herbicides, and their effects on the plant quantity and fresh weight of weeds were higher than 70.00% and 85.00%. Acetochlor and paraquat had certain phytotoxicity to the growth of maize after about 15 days, and its leaves became yellow and grew slowly. On the whole, nicosulfuron had good prevention and control effect on weeds and had no phytotoxicity to the growth of maize.
文摘Trianthema portulacastrum L. （commonly known as horse purslane） is a noxious weed of several economically important field crops in tropical regions of the world. An intensive work on the screening of the biocontrol agents was accomplished through in vitro epidemic study to control weed populations. The foliar disease symptoms on infected weed plants caused by fungal pathogens represented as round to irregular maroon spots with dark borders and the epidemic was identified as leaf spot disease. The pathogen allied with the infection of horse purslane was isolated from infectious propagules by inoculation of leaf bites on a nutrient medium, potato dextrose agar （PDA）. The causal agent of leaf spot was confirmed as Gibbago trianthemae Simmons by Koch＇s postulates. The mycoherbicide ability of G. trianthemae has been examined through visual （standard area diagram） and statistical methods （analysis of variance using the Microsoft Office Excel-Data Analysis Tool Pack 2007）. The results revealed that the pathogen causes significantly （P 〈 0.05） severe infection on host weed and destructs the weed population by leaf spot diseases. The findings of the research suggested that the isolate G. trianthemae is highly virulent and host-specific, and recommended for further studies as a promising biocontrol agent against horse purslane weed.
