Study On The Occurrence And Chemical Control Of Solanum Rostratum In Beijing

Buffalobur (Solanum rostratum Dunal) is an annual weed belong to genus Solanum inSolanaceae family, it originated in North America and spread to China in1981. The spread ofthe invasive plant species caused an increasing threat to native species, agriculture and ourdaily life. It had been an invasive and quarantine weed in China and in great need ofcontrolling.This study focused on the biology, ecology, and chemical management of buffalobur inBeijing. Results obtained are listed as following:1. Buffalobur began to emergence around April20, there were two emergence peaks at theend of April and middle or late May. At the end of May or early June, the weed density ofbuffalobur reached the highest. This period was the critical time for controlling buffalobur.Buffalobur grew very fast from middle of June to July. Buffalobur bloomed after May25andset seeds after June8.2. When herbicides were used as post-emergence treatment, fresh weight inhibition of7herbicides was more than90.0%at recommended dose. The toxicity of bromoxynil octanoatewas the highest, while that of fomesafen was the lowest, the ED90is67.31and795.47g a.i.hm-2, respectively. The order of control efficacy was bromoxynil> fluroxypyr> paraquat>triclopyr> picloram> glyphosate> fomesafen.When herbicides were used as pre-emergence treatment, the control efficacy of acetochlorwas the highest, while that of pendimethalin was the lowest, the ED90were41.43and748.56g a.i.·hm-2, respectively. The order of control efficacy was acetochlor> clomazone>alachlor> s-metolachlor> pendimethalin.3. All of the tested herbicides caused the decline of SPAD value. Paraquat had strongereffects on SPAD, followed by bromoxynil, glyphosate and triclopyr, the other two herbicideshad weaker effects. Herbicides decreased primary light energy conversion (Fv/Fm), PSⅡpotential activity (Fv/F0), actual photochemcial efficiency (Yield) and apparent electrontransfer rate (ETR) of buffalobur leaves. All of these indexes showed a time-effectrelationship to herbicide. To certain degree, the tendency of photochemical quenching (qP)and non-photochemical quenching (NPQ) ascended at the begining and followed by adecrease. Variation of parameters indicated that herbicides inhibited photosynthesys, declinedPS Ⅱa ctivity andblocked electron transfer in buffalobur.