烟草潜叶蛾的药剂防治

１９９３年４～５月在河南省蝇池县进行了８种药剂防治烟草潜叶蛾幼虫的试验。结果表明：８种药剂的平均校正死亡率在施药后２４小时小于３５％，４８小时小于等于５０％，７２小时小于５５％，且各药剂间无显著差异；９６小时有４种药剂的平均校正死亡率达１００％，最低者为７４．４％，且各药剂间差异显著。     

烟草潜叶蛾雌雄蛹的鉴别

为了掌握烟草潜叶蛾Phthorimaea operculella(Zeller)田间种群的性别比例,研究了利用烟草潜叶蛾蛹腹节的外部形态特征区分雌雄蛹的方法.结果表明:雌蛹第8腹节腹面中央有一条较长的纵裂缝,裂缝连接第7和9腹节,且裂缝与第7腹节连接处呈“Y”字形结构,此裂缝由第8腹节上的生殖孔和第9腹节上的产卵孔连接而成.雄蛹第8腹节无裂缝,在第9腹节腹面中央有一较短的纵裂缝.烟草潜叶蛾雌雄蛹的有效区分有利于准确监测其种群的发生动态.     

几种药剂对烟草甲生物活性的测定

为了开发有效的贮烟防护剂,试验了7种药剂对烟草甲幼虫和4种药剂对烟草甲成虫的触杀毒力。结果表明,7种药剂中97.1%氟氯氰菊酯对烟草甲幼虫的致死中量最低,对烟草甲幼虫的触杀毒力最强,其次是98.5%溴氰菊酯,27%高效氯氰菊酯,90%甲基嘧啶磷,65.9%氰戊菊酯;供试药剂中对烟草甲幼虫触杀毒力最弱的是66.67%的甲氨基阿维菌素苯甲酸盐。而对烟草甲成虫触杀毒力最强的是90%甲基嘧啶磷。     

4种杀菌剂对烟草根黑腐病菌的室内毒力测定

采用生长速率法测定了4种杀菌剂对烟草根黑腐病菌[Thielaviopsis basicoht(Berk.and Br.)Ferraris]的室内抑菌毒力.测定结果表明,多菌灵、甲基托布津、大生M-45和杀毒矾等4种药剂对烟草根黑腐病菌的EC50分别为0.4251、5.3134、30.2686和37.2234mg/L,EC90分别为0.8170、11.4312、110.1398和160.5393 mg/L.并且,结合对各种药剂有效成分和作用机理的比较,确定最佳的用药方式为多菌灵与大生M-45交替施用.     

农药混剂对烟草蚜虫的联合毒力测定

在确定的测定条件下 ,采用孙云沛共毒系数法对 9种杀虫剂的 10个组合对烟蚜的联合毒力进行了测定。结果表明 ,共毒系数大于 10 0 ,有增效作用的组合有 :“功夫” +“敌敌畏”、“灭蚜宁” +“敌百虫”、“敌杀死” +“敌百虫”、“西维因” +“敌百虫”和“功夫” +“敌杀死” ,其共毒系数分别为 82 2 .4、795 .5、70 8.3、4 0 0 .9和 30 7.1;其余 5个组合共毒系数小于 10 0 ,表明有拮抗作用。有增效作用的组合可做进一步的室内及田间小区试验     

烟草灰霉病在烟草漂浮育苗中的表现及8种杀菌剂对病菌的室内毒力测定

对引起烟草漂浮育苗中“根茎腐烂病”的病原菌进行了分离鉴定及致病性测定,确定病原菌为灰葡萄孢（Botrytis cinerea Pevs.）。采用生长速率法用8种杀菌剂对其进行了室内毒力测定,结果表明：供试杀菌剂对烟草灰霉病菌菌丝生长的抑制作用存在明显差异,25%咪鲜胺乳油对病菌菌丝生长的抑菌效果最好,其抑制中浓度（EC50）为0.03 mg/L;其次为10%多氧霉素WP、50%秀安WP、58%绿色多菌灵WP、50%速科灵WP、50%农利灵干悬浮剂、20%嘧霉胺悬浮剂,它们对病菌菌丝生长的EC50分别为2.21 mg/ L,3.48 mg/L,6.79 mg/L,23.21 mg/L,24.74 mg/L,34.94 mg/L;80%大生M-45WP的抑制活性最差,EC50为621.36 mg/L。     

四种杀菌剂对烟草青枯病菌的毒力比较

为筛选对烟草青枯病菌更具抑菌作用的杀菌剂,采用"改良抑菌圈法"测定了4种杀菌剂对烟草青枯病菌的毒力。结果表明:4种杀菌剂抑菌率随浓度提高,青枯灵、农用硫酸链霉素和克菌康在1450.0、310.0和700.0 mg·L-1浓度下,72 h时抑菌率分别达到94.3%、89.1%和84.4%,辛菌胺醋酸盐的抑菌率在48 h时达到最高78.1%。4种药剂对烟草青枯病菌的毒力大小依次为农用硫酸链霉素辛菌胺醋酸盐青枯灵克菌康,前两者EC50分别为274.57 mg·L-1和148.25 mg·L-1。表明辛菌胺醋酸盐和农用硫酸链霉素是防控烟草青枯病较为理想的杀菌剂。     

杀虫剂混用对烟蚜的毒力及田间药效试验

试验目的在于为杀虫剂混用提供依据。选用"敌敌畏"1000倍 "敌杀死"2000倍、"功夫"1000倍 "辟蚜雾"1000倍、"氧化乐果"1000倍 "灭蚜宁"1000倍共3种混配杀虫剂进行室内毒力和田间小区药效试验,并与相应单剂作比较。田间药效试验结果表明,"敌敌畏"1000倍 "敌杀死"2000倍有增效作用,另两种混剂分别比对照的1种单剂为增效而比另1种为减效。农药成本混剂介于相应2个单剂之间。     

6种杀菌剂对烟草黑胫病菌的毒力测定

采用生长速率法对"谱克"、"银法利"、"烯酰锰锌"、"敌克松"、"利尔"和"甲霜灵锰锌"6种杀菌剂进行了毒力试验.结果表明:50%"谱克"、68.75%"银法利"和69%"烯酰锰锌"对烟草黑胫病菌菌丝生长均有较好的抑制效果,其中以50%"谱克"的效果最好,其EC50为1.2704 μg/mL;60%"敌克松"、50%"利尔"杀菌剂次之,EC50分别为304.2533 μg/mL和371.1388μg/mL;72%"甲霜灵锰锌"的EC50最高,为610.1751μg/mL.     

Resistance of commercial rice varieties to Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae)

Commercially grown varieties of rice from the United States, France and the Phillipines showed significantly different levels of infestibility by Sitotroga cerealella. The yield obtained by seeding with 200 eggs or with 5 adults is essentially the same. There was an upward trend in yield over six generations on many of the varieties but the change was not often statistically significant. Infestation by eggs appears to be the more dependable method for screening for resistance in rice to this insect.     

Composition and insecticidal activity of essential oil from Pistacia lentiscus L. against Ectomyelois ceratoniae Zeller and Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

This study reports investigations on the chemical constituents and fumigant toxicity of Pistacia lentiscus L. (Anacardiaceae) essential oil against two major stored-date insects, carob moth Ectomyelois ceratoniae Zeller and Mediterranean flour moth Ephestia kuehniella Zeller. Results showed that P. lentiscus essential oil contained terpinene-4-ol (23.32%), α-terpineol (7.12%) and β-caryophyllene (22.62%) as major compounds. Fumigant toxicity tests showed that P. lentiscus oil was more toxic to E. kuehniella (LC₅₀ = 1.84 μl/l, LC₉₅ = 5.14 μl/l) than E. ceratoniae (LC₅₀ = 3.29 μl/l, LC₉₅ = 14.24 μl/l). The fecundity and hatching rate of both insects decreased with increases in concentration or exposure time to the oil. At 136 μl/l air, fecundities and hatching rates were respectively 35 eggs/female and 42.86% for E. ceratoniae and 78 eggs/female and 29.49% for E. kuehniella.     

Egg laying by unmated females of Sitotroga cerealella (Lepidoptera: Gelechiidae)

Ninety-eight out of one hundred unmated females of Sitotroga cerealella laid eggs, the total number ranging between 3 and 94. Sixteen females paired within a day of emergence laid between 91 and 177 eggs, but females not paired until 5 days after emergence laid less than half as many. No egg laid by unmated females was fertile and the fertility of eggs laid by females not paired until 5 days after emergence was also lower than that of eggs laid by females which were paired soon after emergence. Unmated females lived about 15 days; $\text{2}\text{1}\text{2}$ times as long as mated females. When mating was delayed by 5 days the longevity of these following mating, was similar to that of females paired soon after emergence.     

Susceptibility of Sitotroga cerealella (Oliv.) (Lepidoptera: Gelechiidae) to two insect juvenile hormone analogues

The effect of topical application of the insect juvenile hormone analogues methoprene (isopropyl-11-methoxy-3,7-11-trimethyl dodeca-2,4-dienoate) and hydroprene (ethyl-3,7,11-trimethyl dodeca-2,4-dienoate) on last instar larvae and newly-formed pupae of Sitotroga cerealella was examined. Topical application of methoprene at 10 μg/pupa to maize grains containing pupae resulted in 94% adult emergence whereas the same treatment applied to pupae removed from the grains reduced adult emergence to 45%. At 100 μg methoprene/pupa, adult emergence was 91% when grains containing pupae were treated and 32% when pupae were treated after removal from grains. Hydroprene (10 μg/pupa) was more effective than methoprene against insects both inside grains and after removal from grains, giving adult emergence of 48% and 8% respectively. At 100 μg/pupa, hydroprene completely prevented adult emergence when applied to insects removed from the grain. After treatment of the pupal stage with 10 or 100 μg methoprene per insect, adult males produced the same numbers of spermatophores as untreated males and the treatment did not affect either the number or fertility of eggs deposited by adult females.     

World collection rice varieties: Resistance to seed penetration by Sitotroga cerealella (Olivier) (Lepidoptera,Gelechiidae)

Lots of 200 eggs of Sitotroga cerealella (Olivier) were placed on 10 g samples of 780 varieties of rice from the U.S.D.A. World Collection. An average of 91% of the eggs hatched and between 1 and 83% of the larvae from these reached the adult stage and emerged. Less than 10% survived in 102 varieties. Graphic data exhibit a bimodal shape, indicating that two resistance bases operated against these insects; both apparently acted to prevent kernel entry by the freshly hatched larvae.     

The influence of photoperiod on the life-cycle of Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae)

Diapause in fully grown larvae of Ectomyelois ceratoniae was induced by low temperature and short photoperiods. When larvae were reared at 30°C, 70% r.h. there was no diapause in a light regime of 12 hr light followed by 12 hr darkness (12L/12D), and only 20% entered a weak diapause in continuous darkness. However, at 20°C, 70% r.h. there was no diapause in 16L/8D but almost all larvae entered diapause in 12L/12D. At 20°C diapause delayed adult emergence by an average of 111 days, compared with about 50 days at 30°C. Survival to adult at 30°C was 75% or more at most photoperiods, but at 12L/12D and 13L/11D it was less than 50%. At 20°C survival was about 70% at the two photoperiods tested.

A slight effect of photoperiod on non-diapause growth rates was observed. Above 16 hr light longer photoperiods reduced the mean developmental period from egg hatch to adult emergence, by 4 days at 20L/4D and 6 days at 24L/0D.

The significance of diapause in this species in relation to its potential as a pest is discussed.     

The influence of temperature and humidity on the life-cycle of Ectomyelois ceratoniae (Zeller) (Lepidoptera: Phycitidae)

Adults of Ectomyelois ceratoniae would not mate in small containers kept in constant conditions. Mating occurred and fertile eggs were laid when the adults were placed in a large conical cage, kept in regularly fluctuating conditions of light, temperature and humidity resembling their native habitat. The dusk/dawn light intensity changes were particularly important. Most mating and oviposition occurred from dusk until the following dawn, with adults motionless during daylight.At 70% r.h. eggs hatched on average in 4·2 days at 25°C, 3·0 days at 30°C and 3·6 days at 35°C. At 30°C, this period varied from 3·4 days at 30% r.h. to 3·0 days at 90% r.h. On a diet of soybean meal, sucrose and water at 30°C, the larval period averaged 30 days at 30% r.h., 13 days longer than at 70% r.h., and the low relative humidity also increased larval mortality. At 90% r.h., no larvae emerged from food that became very mouldy. The total developmental period from egg hatch to adult emergence at 70% r.h. averaged 48 days at 20°C, 30 days at 25°C and 23 days at 30°C.     

Chemotaxis of Habrobracon hebetor (Say) (Hymenoptera: Braconidae) in response to larvae of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) and host food substrate with tobacco

Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is one of the most studied parasitoids for biological control of pest’s moths in postharvest environment. However, little is known about the searching behavior and learning ability of this braconid regarding host localization. Thus, this study aimed to evaluate the chemotaxic behavior of female H. hebetor with and without parasitism experience to olfactory signals associated with types of stored tobacco and white wheat flour, and the presence of the host Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) developed in different diets. The chemotaxic responses of 2-4 day old H. hebetor females with and without previous experience of parasitism were observed in a “Y” type olfactometer. The odors of Virginia and Burley tobacco, wheat flour and E. kuehniella larvae reared with or without tobacco in their diet were evaluated. As a control, only air was used. Females of H. hebetor with no previous experience of parasitism were more responsive to both the host larvae and the different food substrates contrasted with air. In relation to tobacco substrate, both Virginia and Burley, when contrasted with larvae that developed in diet with tobacco, females were more responsive to tobacco volatile. On the other hand, mostly H. hebetor females with parasitism experience were more attracted to host larvae when compared to substrates. The number of non-responsive females with parasitism experience, was significantly lower than in the group of females without experience. Through previous experience, the parasitoid was able to develop associative learning, which may increase the efficiency of host search. This is the first record of tobacco attractiveness for the parasitoid H. hebetor, an important aspect for the success of biological control programs in tobacco storage.