黑龙江省西北部地区向日葵田杂草调查

为了明确黑龙江省西北部地区向日葵田杂草发生危害情况,于2009年和2012年对该地区向日葵田进行了杂草调查。结果表明:该地区向日葵田杂草有22科62种。2a发生频率均在50%以上的杂草有8种,分别为稗草、反枝苋、藜、本氏蓼、苍耳、狗尾草、金狗尾草和苣荬菜,这8种杂草可视为黑龙江省西北部地区向日葵田的主要优势杂草。

240g/L收乐通EC加助剂防除向日葵田禾本科杂草的效果

为了增加防除向日葵田禾本科杂草除草剂种类的选择性，便于药剂的交替使用，延缓杂草抗药性的产生，延长除草剂的使用寿命。2012年应用240g/L收乐通EC 45-100mL/667m^2，以及各处理加入等量Amigo助剂，于向日葵生长期，杂草3-6叶期进行茎叶喷雾处理防除田间禾本科杂草试验。结果表明：试验药剂单剂各处理对于一年生禾本科杂草稗草的速效性、持效性和防效均很好，药后15d、35d防效均稳定在94.3%以上，而且与10.8%高效氟吡甲禾灵EC和10%精喹禾灵EC两种对照药剂防效相当；对于多年生芦苇施药后35d鲜重防效为56.9%-76.5%，不如对照药剂10.8%高效氟吡甲禾灵EC和10%精喹禾灵EC处理88.9%、91.6%的防效。但是，收乐通各处理加入等量助剂后防效明显提高，药后35d对芦苇的鲜重防效为55.8%-98.9%，其中240g/L收乐通 EC 80mL/667m^2、100mL/667m^2处理防效均在93.1%以上，优于两种对照药剂，而且对向日葵安全。

黑龙江省东部地区向日葵田杂草调查初报

采用倒置"W"9点取样法,对黑龙江省东部地区向日葵田杂草进行调查。结果表明:该地区向日葵田杂草有20科55种,其中阔叶杂草17科43种占78.2%,禾本科杂草9种占16.4%,其它3种(鸭跖草科、百合科、木贼科各1种)占5.5%。一年生杂草30种占54.5%,一年生或越年生杂草7种占12.7%,多年生杂草18种占32.7%。出现频率50%以上的杂草10种,分别为稗草、藜、铁苋菜、香薷、金狗尾草、苣荬菜、苍耳、问荆、反枝苋、鸭跖草,这10种杂草可视为东部地区向日葵田的主要优势杂草。

赤峰地区向日葵田杂草发生情况及除草剂应用现状

通过调查赤峰地区向日葵田杂草种类、发生情况及向日葵除草剂应用现状,梳理了向日葵田化学除草中存在的问题,为当地向日葵生产田杂草的有效防除和化学除草剂的科学应用提供参考。

Seed bank dynamics of an invasive alien species, Helianthus annuus L.

Aims The ability to form persistent seed banks is one of the best predictors of species’potential to establish in new ranges.Wild sunflower is native to North America where the formation of persistent seed banks is promoted by disturbance and it plays a key role on the establishment and persistence of native populations.However,the role of the seed banks on the establishment and persistence of invasive populations has not been studied.Here,we evaluated the role of seed bank and disturbance on the establishment and fitness,and seed persistence in the soil in several sunflower biotypes collected in ruderal(wild Helianthus annuus)and agrestal(natural crop–wild hybrid)habitats of Argentina as well as volunteer populations(progeny of commercial cultivars).Methods In a seed-bank experiment,we evaluated emergence,survival to reproduction,survival of emerged seedlings,inflorescences per plant and per plot under disturbed and undisturbed conditions over 2 years;in a seed-burial experiment,we evaluated seed persistence in the soil over four springs(6,18,30 and 42 months).Important Findings Overall,seedling emergence was early in the growing season(during winter),and it was promoted by disturbance,especially in the first year.Despite this,the number of inflorescences per plot was similar under both conditions,especially in ruderals.In the second year,emergence from the seed bank was much lower,but the survival rate was higher.In the seed-burial experiment,genetic differences were observed but seeds of ruderals and agrestals persisted up to 42 months while seeds of the volunteer did not persist longer than 6 months.The agrestal biotype showed an intermediate behavior between ruderals and volunteers in both experiments.Our findings showed that wild and crop–wild sunflower can form persistent seed banks outside its native range and that disturbance may facilitate its establishment in new areas.