无瓣海桑主要害虫绿黄枯叶蛾的取食行为研究

绿黄枯叶蛾Trabala vishnou Lefebure是红树林植物无瓣海桑Sonneratia apetala Buch-Ham的重要害虫,为制定科学的防治指标和防治策略,对该虫的取食行为和取食量进行了初步的研究。结果表明:绿黄枯叶蛾幼虫喜食无瓣海桑、尾巨桉,拒食秋茄、桐花树;幼虫5龄,1～3龄幼虫具有聚集性,4龄幼虫开始分散取食;1～2龄幼虫取食量少,3～5龄取食量占整个幼虫期取食量的98.12%,其中5龄幼虫的取食量占整个幼虫期取食量的74.52%;幼虫期平均取食无辨海桑叶片178.94 cm2/头,确定防治指标为9.8头/千叶。     

弧目大蚕蛾幼虫取食量研究

弧目大蚕蛾Neoris haraldi Schawerda幼虫5龄,平均龄期29.67 d。1龄幼虫取食量较少,平均日取食叶面积为4.25 mm2,2龄幼虫平均日取食叶面积为7.00 mm2,3龄幼虫取食量猛增,平均日取食叶面积为83.06 mm2,4龄幼虫平均日取食叶面积为231.90 mm2,5龄幼虫平均日取食叶面积为278.86 mm2。2龄以前幼虫食量较小,仅占全部食量的1.19%;3龄后幼虫食量占全部食量的98.81%。5龄幼虫日均食量较多,取食天数也达到8 d,占总取食量的52.35%,危害也较2龄以前的幼虫严重。弧目大蚕蛾幼虫头宽、体长、体重、取食量与龄期相关极显著。     

桑天牛幼虫龄数林间识别研究

通过室内饲养繁殖和野外采集,获得含有各龄桑天牛幼虫的杨树枝干,室内条件下分龄收集幼虫虫粪。对各龄幼虫虫粪进行区分,分离出粪粒和啃食残渣,对最末排粪孔长径和短径以及粪粒的理化性质与龄数关系进行研究。结果表明:桑天牛幼虫粪粒平均宽度值为1.211 5 mm,平均长度值为2.101 8 mm;粪粒中木屑平均宽度值为0.113 0 mm,平均长度值为0.207 3 mm;粪粒中蛋白质的平均含量为0.142 6%,总糖的平均含量为0.612 5%,纤维素平均含量为46.72%,木质素平均含量为16.12%。最末排粪孔长径和短径、粪粒长度和宽度、粪粒中木屑长度和宽度、纤维素含量、蛋白质含量均与幼虫龄数存在线性相关性,可作为快速识别幼虫龄数的指标,其中粪粒宽度比较稳定,在各龄数间无重叠,为林间快速识别虫龄的最佳指标。     

白蜡窄吉丁幼虫的龄数和龄期测定

采用林间定期调查取样的方法，测定白蜡窄吉丁幼虫的龄数以及各龄的龄期；分别测量不同发育阶段幼虫的体长、体宽(第7腹节最宽处)、前胸背板宽、口缘宽、尾又长和尾叉前缘宽等6项指标，以期找出区分和判定幼虫虫龄的最佳形态特征及指标。结果表明：白蜡窄吉丁幼虫有4龄，尾又及其长度可作为理想的分龄特征和分龄指标；幼虫的口缘宽度也可作为指标之一；体长、体宽、前胸背板宽和尾又前缘宽变异较大，不宜用于分龄。研究还发现：幼虫尾叉内侧的形态特征是区分幼虫虫龄的简洁而方便的方法。利用种群众数龄期法测定各龄的平均龄期分别为：1龄18．1d，2龄11．2d，3龄10．7d，4龄261．2d，幼虫期共为301．3d。     

美国白蛾的生物防治研究

作者通过浸虫法和浸叶法分别测定了苦参碱和虫酰肼对美国白蛾3龄幼虫的室内生物活性,结果如下:苦参碱对美国白蛾3龄幼虫的毒力回归方程为y=4.043 9+0.713 1x,其致死中浓度LC50为21.915 2 mg/L,LC90为1 373.543 9 mg/L;虫酰肼对美国白蛾的毒力回归方程为y=4.431 2+0.689 1x,其致死中浓度LC50为6.689 6 mg/L,LC90为484.307 mg/L。     

噻虫胺·高效氯氟氰菊酯微囊悬浮剂防治落叶松毛虫高龄幼虫的试验效果

落叶松毛虫(Dendrolimus superans)在春季大发生时多为3~6龄,可造成严重危害。通过使用噻虫胺·高效氯氟氰菊酯微囊悬浮剂对春季高龄幼虫进行防治试验,结果表明:使用该药剂稀释1000倍液防治3~6龄幼虫见效快、效果好;虫口密度不高时可采用1800倍液喷雾施药;防治3龄以下幼虫,可稀释2500倍液喷雾防治。     

马尾松毛虫抗药性监测及增效磷与3种菊酯混配的增效作用

对江西高安等16个县、市林区的马尾松毛虫用溴氰菊酯、氰戊菊酯和氯氰菊酯用点滴法进行毒力测定，结果表明，江西林区马尾松毛虫对溴氰菊酯的耐药力有明显提高，其中高安、贵溪林区马尾松毛虫的抗数达到了低抗水平，马尾松毛虫对氰戊菊酯和氯氰菊酯尚未产生抗性，室内用以上3种拟除虫菊酯与增效磷（SV1）按1：0．5、1：1、1：3、1：5T 1：10的比例混配，用点滴法对马尾松毛虫进行毒力测定，结果表明，增效磷与拟除虫菊酯混配有明显的增效作用，并且随着SV1比例的提高，增效作用增强，用4种拟除虫菊酯杀虫剂（2．5％溴氰菊酯、20％ 酯、2．5％三氟氰菊酯和10％氯氰菊酯）加增效磷按不同混配比进行林间防马尾松毛虫试验，结果表明，增效与拟除虫菊酯杀虫剂混配有极显著的增效作用，林间防治松毛虫以溴氰菊酯＋SV1（1：5）、氰戊菊酯＋SV1（1：3－1：5）、三氟氰氯菊酯＋SV1（1：3－1：5）以及氯氰菊酯＋SV1（1：5）稀释8000倍效果最佳。     

Impact of neem and chinaberry fruit extracts on the pest/parasitoid (Pieris rapae/Hyposoter ebeninus) interactions

A new technique was performed to simulate exposure of the host Pieris rapae larvae to both botanical treatment and the parasitoid Hyposoter eheninus in different sequences. It was found that: host larvae subjected to both parasitoid and 1?% neem treatment showed significant or insignificant reductions both in pupal formation as well as adult emergence percentages when treatment preceded or followed parasitism, respectively. Both neem treatments revealed significant prolongation in the development of unparasitized and parasitized larvae (on average 4 to 5 days delay), whereas chinaberry caused significant prolongation only among parasitized larvae (on average 2.7 days delay in egg-larval duration). Fate of parasitism among untreated hosts was found to be faster than among neem-treated ones. Parasitism percentages among 1 and 0.5?% neem-treated third instar host larvae held 7 days before parasitism reached 3 and 2 times that achieved among those reared on untreated diet for the same period, ­respectively. It was concluded that prolongation of the preferred target instars of the host, due to neem treatments, increased the chance for parasitism. Nevertheless, treatment with neem at the LC₅₀ level exhibited a great reduction in parasitoid progeny. However, a lower concentration (LC₂₅) could reasonably potentiate parasitism without drastic losses in parasitoid emergence.     

苹小吉丁(鞘翅目：吉丁甲科)幼虫龄数的测定

In recent years, Agrilus mali Matsumura has outbroken in the Xinjiang wild fruit forest, and become the primary threat to Malus sieversii. In early study, the larvae of Agrilus mali were divided into six instars. However, the particular reason and method were not mentioned, and the larvae of Genus Agrilus were usually divided into four or five instars. For better pest forecasting and control strategies, the determination of larval instars was studied again. A.mali larvae were sampled periodically in forest, and the eggs were collected to hatch the first instar larvae. Three characteristics (i. e. peristoma width, urogomphus length and body length) were measured by binocular microscope with an eyepiece micrometer. According to the Dyar's law, the data were managed with frequency analysis, and examined by one-way ANOVA method, Crosby ratio and checked with larvae which were molting when sampling. The results showed that, the A. mali larva has five instars, and all three determination characteristics are effective except body length.