Tree Mortality,Needle Biomass Recovery and Growth Losses in Scots Pine Following Defoliation by Diprion pini (L.) and Subsequent Attack by Tomicus piniperda (L.)

Tree mortality and growth losses following insect defoliation are poorly documented in Scandinavia. In 1990-1991, Diprion pini (L.) caused extensive defoliation to Scots pine in Lauhanvuori national park and surrounding areas in south-western Finland. Most trees lost all their foliage in 1990. In 1991, the outbreak area was sprayed with diflubenzuron (Dimilin®), except in the national park, where trees were severely defoliated again. No further defoliation occurred in 1992. In spring 1993, sprayed trees had ca 30% foliage, whereas unsprayed trees on average carried less than 10% of full foliage. The latter trees were susceptible to attack by Tomicus piniperda (L.), whereas the former largely escaped beetle attack. Beetle attacks peaked in 1993, and depletion of suitable host trees probably terminated the beetle outbreak in the area. Two years of severe defoliation resulted in substantial tree mortality and growth losses. In spring 1997, these unsprayed stands had suffered a ca. 50% loss in basal area which was mainly because of mortality, and about half of the dead trees had been attacked by T. piniperda. Surviving trees had ca 50% of full foliage, and radial growth had still not recovered. Basal area growth was reduced by 40-70%, depending on the amount of foliage left after the second year of defoliation. In contrast, tree mortality and beetle attack in the sprayed stands were negligible, and these trees had recovered full foliage and radial growth by spring 1997. Thus, one year of total defoliation resulted in an estimated loss in basal area growth of approximately 30% during ca. 5 yrs. In conclusion, the spraying operation was economically justified, as it prevented substantial tree mortality and reduced growth losses.     

灭幼脲Ⅰ号对鹌鹑毒性的研究

用25％灭幼脲Ⅰ号可湿性粉剂0.4克/日量,0.8克/日量和1.6克/日量各饲养10头幼鹌鹑连续一月,结果对鹌鹑的体重、产卵量、卵的大小均无影响。对鹌鹑血液进行生化测定,其中血清蛋白含量、血清核酸含量、血清含糖量与对照无显著差异,仅GPT稍偏高。因此在正常浓度使用下,灭幼脲Ⅰ号对鹌鹑是安全的。     

灭幼脲Ⅰ号胶悬剂对家禽安全性的试验

使用灭幼脲Ⅰ号防治森林害虫,必须考虑到它对家禽以至鸟类的影响。其试验方法是,将灭幼脲Ⅰ号混入家禽饲料中,每只鸡每日饲喂药量为每公斤体重1—2g,试鸡为成鸡,连续饲喂14—15天,通过体重、羽毛、冠色和产蛋等观察、检验,均无影响。对血清白蛋白、总蛋白、胆碱酯酶、谷丙转氨酶和血液葡萄糖等生理指标进行测定均无改变。由此可见,灭幼脲Ⅰ号在防治生产中,对家禽是安全的。     

灭幼脲3号和阿维菌素对舞毒蛾幼虫药效试验简报

灭幼脲3号、阿维菌素是无公害生物杀虫剂。笔者采用灭幼脲3号、阿维菌素，对为害麻栎的舞毒蛾幼虫进行了防治试验．并与来福灵、敌敌畏和氧化乐果等化学农药进行对比；结果表明，灭幼脲3号和阿维菌素与其它三种化学农药具有同等的防治效果。     

灭幼脲Ⅲ号对白蛾周氏啮小蜂的安全性测试

研究了灭幼脲Ⅲ号对白蛾周氏啮小蜂成虫的室内毒性试验,结果表明:先放蜂再施药的试验前3 d的不同浓度处理之间以及各浓度处理、清水对照之间对白蛾周氏啮小蜂的毒性无明显差异;先施药再放蜂的试验,在不同的施药天数、处理和处理以及处理和清水对照之间对白蛾周氏啮小蜂的毒性也不存在明显差异。这说明灭幼脲Ⅲ号对周氏啮小蜂成虫不具有毒性作用或毒性作用很小。     

灭幼脲Ⅰ号防治林业害虫的研究

1984—1987年在黑龙江、辽宁等4省9个市县,对松毛虫、杨毒蛾等7个虫种进行6274 ha大面积防治试验取得成功。不论地面和飞机防治均取得了90％以上的理想效果。灭幼脲Ⅰ号是抑制昆虫几丁质合成的药剂,经测定可抑制松毛虫几丁质合成达11—30％。该药能使昆虫在蜕皮或变态中产生障碍而致死。对人、畜安全;对环境无公害;对鱼类、鸟禽类、蜜蜂等均无杀伤作用。对天敌昆虫较安全,由于保护了天敌,增强了森林自控能力,促进了生态平衡。它是目前取代有机氯杀虫剂,克服害虫对有机磷和菊酯类抗药性的一种仿生药剂,可以在害虫综合治理(IPM)中广泛推广使用。