6种长效除草剂土壤残留致烟草药害 症状及其致害临界值

采用盆栽试验方法,测定氯嘧磺隆尧苯磺隆、烟嘧磺隆、莠去津、扑草净及氟磺胺草醚6种长效除草剂土壤残留致烟草药害症状及其致害临界值。结果表明：6种长效除草剂的施药方式均为土壤处理,所以均不同程度地抑制烟株的根、茎、叶的生长。氯嘧磺隆、苯磺隆、烟嘧磺隆3种磺酰脲类除草剂致使烟株药害症状显现时间长,持续时间长,不易恢复;而莠去津、扑草净尧氟磺胺草醚则显现时间短,轻者可恢复,严重者可使烟株迅速枯萎死亡。氯嘧磺隆、苯磺隆、烟嘧磺隆、莠去津、扑草净、氟磺胺草醚（有效成分）致烟株药害的临界值分别为：5.31×10-3、2.79×10-3、1.05×10-2、3.35×10-3、2.00×10-3、1.11×10-4 mg/kg。     

除草剂产生药害的原因和防治技术

阐述了除草剂在使用过程中存在的问题及其药害产生的原因,并提出了除草剂的安全使用方法和除草剂药害的主要救治措施。     

Effect of Diclofop and Linuron on Rye Grass (Lolium multiflorum), Control in Triticale (X Triticosecale), Wheat (Triticum aestivum), and Rye (Secale cereale)

Annual rye grass ( Lolium multiflorum Lam.) is a serious and wide spread problem in cereal crops. A field experiment with a promising herbicide diclofop [(±)-2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid] at 0.56, 0.84 and 1.12 kg ai/ha, in comparison to commonly used linuron [ N' -(3,4-dichlorophenyl)- N -methoxy- N -methylurea] at 0.84, 1.12 and 1.41 kg ai/ha was conducted to control rye grass ( Lolium multiflorum Lam.) in triticale (X Triticosecale Wittmack), wheat ( Triticum aestivum L.) and rye ( Secale cereale L.). The herbicides were applied as soil-incorporated, preemergence and post-emergence. Results showed that diclofop is less phytotoxic than Linuron and the postemergence application of these herbicides was more phytotoxic on all cereal crops. Diclofop applied at 1.12 kg/ha, gave almost 100 percent rye grass control and produced 45 and 115 kg/ha higher grain yields in pre- and postemergence methods, respectively, as compared to the soil-incorporated method.     

Role of underground parts of barnyardgrass (Echinochloa crus-galli (L.) Beauv. var. formosensis Ohwi) in its sensitivity to thenylchlor in soil

In the present study, the phytotoxic activity of top-soil applied with thenylchlor [2-chloro- N -(3-methoxy-2-thieny)-2',6'-dimethylacetanilide] on the growth of rice ( Oryza sativa L.) was dependent on the emergence depth in soil but its activity on barnyardgrass ( Echinochloa crus-galli (L.) Beauv. var. formosensis Ohwi) was only slightly affected by the emergence depth. However, the phytotoxic activity on barnyardgrass and rice was similar irrespective of the different emergence depths in its treatment to all soil layers. Thenylchlor treatment to the mesocotyl of barnyardgrass induced significant inhibition of shoot elongation, whereas the treatment to the coronal root only inhibited the coronal elongation without inhibiting shoot elongation. Absorption and translocation of ¹⁴C-thenylchlor in barnyardgrass were determined in water culture. The different amounts of radioactivity per plant among the treatments to the underground parts were due to the plant part that came in contact with ¹⁴C-thenylchlor. The radioactivity per dry weight was found to be higher in the basal part of the shoot than in its upper part in all treatments to the underground parts. It was suggested that the phytotoxic activity of thenylchlor on the growth of barnyardgrass in soil is induced by its accumulation in the basal part of the shoot through translocation. This primarily occurs after the absorption substantially by the mesocotyl from the herbicide-treated layer and additionally by other underground parts.     

Evaluation of phytotoxic effects ofGliricidia sepium (Jacq.) Walp prunings on maize and cowpea seedlings

Phytotoxic effects ofGliricidia prunings were tested on maize seedlings in the laboratory and on maize and cowpea seedlings in the field. In the laboratory test, growth of maize seedlings was significantly depressed by addition of leachate ofGliricidia prunings. In the field, leaf, chlorosis of maize and cowpea seedlings occurred when mulched withGliricidia prunings; number of affected leaves increased with increasing mulch rate. Maize was more susceptible than cowpea. This phytotoxic effect, however, did not reduce growth of maize and cowpea seedlings in the field. ApplyingGliricidia mulch one week before planting eliminated the phytotoxic effects on maize.     

发酵床养猪垫料的养分转化与植物毒性研究

发酵床养殖技术也被称为原位堆肥技术,是一种值得推荐的控制畜场粪便排放与污染的生态养殖模式。本研究检测了发酵床的水分、温度和pH值变化以及在连续饲养两批猪后垫料中碳、氮和磷的组成与含量变化情况及其对植物毒性的强弱。结果表明,发酵床使用期间水分为58%~61%,垫料内部温度维持在40~55℃;在连续饲养两批猪后,垫料的pH值升高至8.16,氮、磷含量显著提高,铵态氮、亚硝态氮和硝态氮浓度显著升高,C/N比由养猪前的84∶1下降至31∶1,N/P比由2.8∶1下降至1.26∶1;垫料中的总铜浓度由7mg·kg-1升高至89mg·kg-1。以白菜种子作发芽试验考察废弃垫料的植物毒性,其相对发芽率为86.67%,相对根长为132.95%,发芽指数(Germination Index,GI)为115.23%,说明饲养了两批肥猪的发酵床垫料无植物毒性作用,对根的生长有促进作用,可作为有机肥还田。     

不同药剂对山银花蚜虫的防治效果研究

10种不同药剂防治危害山银花的胡萝卜微管蚜的药效试验结果表明:25%吡蚜酮悬浮剂1 500倍药液、0.36%苦参碱3 000倍药液、10%烯啶虫胺3 000倍药液等3个药剂处理防治山银花蚜虫效果较好,且其用药成本较低,低毒,对山银花害虫捕食性天敌杀伤力小,在生产上可进行推广使用。     

烟嘧磺隆对夏玉米药害原因分析及对策

烟嘧磺隆是夏玉米田常用的苗后茎叶处理除草剂,由于高温时期用药、随意加大用药量、对水量过少和使用器械不当等原因,造成玉米药害时有发生。通过控制用药时期、选择适宜施药时间、严格用药量和对水量、提高药剂喷雾技术、保证与有机磷农药间隔期等措施,可有效预防烟嘧磺隆药害的发生。如发生药害可采取摘除卷曲心叶、摘除过多的蘖芽和加强田间栽培管理等措施,可减轻药害损失。     

Phytotoxic and antiphytopathogenic compounds from Thai Alpinia galanga (L.) Willd. rhizomes

The management of weeds and diseases that are caused by phytopathogenic fungi is important for preventing the loss of agricultural products. The aim of the present study was to identify phytotoxic and antiphytopathogenic agents from the Thai Alpinia galanga rhizome. Extracts of the dried rhizomes of A. galanga (Zingiberaceae) were separated and tested for phytotoxic activity against lettuce (Lactuca sativa L. cv. Great Lakes) and Italian ryegrass (Lolium multiflorum Lam. cv. Wasefudou) and for antiphytopathogenic activity against Alternaria porri, Colletotrichum gloeosporioides, Fusarium oxysporum and Phytophthora nicotianae. 1′‐Acetoxychavicol acetate ( 1 ) was identified as one of the main components, together with trans‐p‐coumaryl acetate ( 3 ) and trans‐p‐acetoxycinnamyl acetate ( 2 ). 1′‐Acetoxychavicol acetate ( 1 ) was solvolyzed with 2% EtOH to yield trans‐p‐coumaryl ethyl ether ( 6 ), trans‐p‐coumaryl acetate ( 3 ) and trans‐p‐coumaryl alcohol ( 5 ). 1′‐Acetoxychavicol acetate ( 1 ) completely inhibited the root growth of the lettuce seedlings at 50 μg mL^–1, but had a weaker inhibitory effect on the growth of Italian ryegrass. 1′‐Acetoxychavicol acetate also inhibited the growth of P. nicotianae and A. porri, with minimum inhibition concentration values of 15.6 and 31.5 μg mL^–1, respectively. The plant growth‐inhibitory activity and fungal growth‐inhibitory activity of trans‐p‐coumaryl acetate ( 3 ), trans‐p‐coumaryl ethyl ether, trans‐p‐coumaryl alcohol ( 5 ) and trans‐p‐acetoxycinnamyl acetate ( 2 ) were lower than those of 1′‐acetoxychavicol acetate. A structure–activity relationship suggested that the strong phytotoxic and antiphytopathogenic activity of 1′‐acetoxychavicol acetate relied on the 1′‐acetoxyl group.     

不同化学农药处理对甜瓜商品性的影响

试验针对设施甜瓜的主要病害,开展不同农药、甜瓜品种、农药浓度及施用时间对商品性的影响试验。结果表明:蜜雪华和№1对农药敏感,农药对先甜红玉和薄皮脆危害较小;72.2%普力克SC和58%甲霜灵锰锌WP对蜜雪华危害较小,各种农药随着浓度的降低,对甜瓜危害程度降低。