水稻品种贮藏期对谷蠹抗性的研究

本研究测定了42份水稻品种在贮藏期间对谷蠹的抗性,结果得出具有抗级的稻种共有15份,中抗品种共有16份.抗性机制研究结果分析表明:谷粒的裂颖率与敏感度系数、稻谷受害损失率关系密切.呈极显著的正相关.而抗性与谷粒化学成份中的粗蛋白、总淀粉、支链淀粉、直链淀粉的含量和糊化温度皆无明显的相关关系.     

两种重要储粮害虫的无公害防治技术研究

通过３种虫生真菌、2种苏云金杆菌粉剂(Bt-1和Bt-2)及48%乐斯本乳油对生活在小麦中的谷蠹、长角扁谷盗进行毒力试验,结果表明：Bt-1粉剂对两种储粮害虫具有较高的毒力,对谷蠹LD50为15.75ug/g,对长角扁谷盗LD50为8.06ug/g;三种虫生真菌对这两种害虫侵染力较弱,最高校正死亡率仅为55.0%。48%乐斯本乳油对两种储粮害虫的熏蒸效果较好,在0.80ml/L浓度下,谷蠹、长角扁谷盗死亡率均达到100.0%。     

The action of phosphine against the eggs of phosphine-resistant and -susceptible strains of Rhyzopertha dominica F

The effect of phosphine at exposure periods of 24, 48 and 120 h on hatching and mortality of 0- to 1-day-old eggs of susceptible (TN6) and resistant (FC10) strains of Rhyzopertha dominica of field origin was investigated. The fumigant affected hatching in both the strains. In a 48-h exposure at 27 (+/- 2) degrees C, the LD99 doses for the eggs of TN6 and FC10 were 0.56 and 3.25 mg litre-1, respectively. Significant reduction in hatching was observed in treated batches with progressive increase of phosphine dose in the first 2-3 days. On subsequent days the numbers hatching were often similar to those in controls, and sometimes exceeded control hatch, especially following a 5-day exposure. A critical change in the order of susceptibility of egg and adult stages of the two strains was noticed. In 48-h exposures, eggs of the susceptible strain were more tolerant than their adults, whilst the reverse was true in the resistant strain.     

Effect of exposure period on degree of dominance of phosphine resistance in adults of Rhyzopertha dominica (Coleoptera: Bostrychidae) and Sitophilus oryzae (Coleoptera: Curculionidae)

Degree of dominance of phosphine resistance was investigated in adults of Rhyzopertha dominica F and Sitophilus oryzae L. Efficacy of the grain fumigant phosphine depends on both concentration and exposure period, which raises the possibility that dominance levels vary with exposure period. New and published data were used to test this possibility in adults of R dominica and S oryzae fumigated for periods of up to 144 h. The concentrations required for control of homozygous resistant and susceptible strains and their F1 hybrids decreased with increasing exposure period. For both species the response lines for the homozygous resistant and susceptible strains and their F1 hybrids were parallel. Therefore, neither dominance level nor resistance factor was affected by exposure period. Resistance was incompletely recessive and the level of dominance, calculated at 50% mortality level, was -0.59 for R dominica and -0.65 for S oryzae. The resistant R dominica strain was 30.9 times more resistant than the susceptible strain, compared with 8.9 times for the resistant S oryzae strain. The results suggest that developing discriminating doses for detecting heterozygote adults of either species will be difficult.     

Mortality and F1 progeny of the lesser grain borer, Rhyzopertha dominica (F), on wheat treated with diatomaceous earth: effects of rate, exposure period and relative humidity

A series of experiments at 25 (+/-1) degrees C were conducted in which different application rates of diatomaceous earth (DE) formulation Protect-It at two levels of relative humidity, 40 and 55%, and at three exposure periods were evaluated for control of Rhyzopertha dominica (F). Test insects were placed in vials containing 40 g of soft winter wheat mixed with 0.25, 0.50, 1.00, 1.50 and 2.00 g DE kg(-1). At all rates except 0.25 g kg(-1), mortality was significantly different from that in the control at the relevant exposure period. After each exposure interval, dead and live insects were counted and removed, and the vial containing wheat was then returned to the appropriate humidity chamber for 8 weeks until F(1) adults emerged. F(1) progeny production was significantly different from the control group at all rates. Mortalities for 1, 2 and 3 weeks exposure were found to be 47 (+/-5)%. Despite the fact that mortality increased with increasing rate, total mortality was not achieved even at the highest rate of DE. F(1) progeny production decreased with increasing rate for both RH conditions, and containment of population for both RH conditions was achieved at 1.00 g DE kg(-1). For each exposure period, F(1) progeny production of R dominica decreased with increasing rate of DE, and population suppression was achieved at 1.00 g DE kg(-1) for all exposure intervals. In summary, Protect-It resulted in reduced F(1) adult progeny and containment of population was achieved at 1.00 g DE kg(-1) at which rate mortality was 77%.     

八种药用植物精油对谷蠹成虫的熏蒸活性

采用三角瓶密闭熏蒸法,测试了8种药用植物精油在空仓和实仓模拟条件下对谷蠹成虫的熏蒸活性。结果表明,8种植物精油以八角茴香,小茴香和石菖蒲对试虫的熏杀效果较好,尤以八角茴香精油的熏杀效果最佳。空仓模拟条件下,八角茴香和小茴香精油均对谷蠹成虫表现出很高的熏杀活性,其熏蒸处理3 d后的LC50分别为2.88μL.L-1和4.02μL.L-1。实仓模拟条件下,8种植物精油仅以八角茴香的熏蒸效果较好,其166.67μL.L-1熏蒸处理10 d后试虫的校正死亡率为92.37%,实仓模拟熏蒸处理14 d后的LC50为67.01μL.L-1。     

谷蠹的生物学特性与防治方法

文章对谷蠹生物学、生态学特性，谷蠹抗药及谷囊防治方法进行了综述。     

农户储粮害虫发生规律观察

农户储粮害虫以玉米象、麦蛾、书虱为主,以户计算的发生率为100%,锈赤扁谷盗、赤拟谷盗、米扁虫、谷蠹的发生率依次是20%、16.7%、16.7%、13.3%。随着仓温不断上升,4月上中旬开始见到玉米象、麦蛾成虫活动;7月中旬至8月中旬,仓温上升至30℃,经过3~4个月的发育、繁殖,玉米象、麦蛾虫口密度大,成虫活动频繁,并一直维持到9月下旬至11月中旬。气温为0~8℃的12月,也有玉米象、麦蛾的成虫活动。由于农户粮堆较小、天敌较多,因此,农户储粮害虫防治应以装具、清洁为主,以储粮防护剂为辅。     

水菖蒲两种提取方法粗提物对谷蠹和玉米象的触杀活性

为进一步开发利用植物源杀虫剂,实现安全和绿色储粮,分别以甲醇冷浸法、超临界CO2萃取法（SFE-CO2）对水菖蒲Acorus calamusL.根茎中的生物活性物质进行提取,采用药膜法研究了水菖蒲提取物对谷蠹Rhyzopertha dominica Fabricius、玉米象Sitophilus zeamais Motschulsky成虫的触杀活性。结果表明：甲醇冷浸法、SFE-CO2对水菖蒲根茎的提取率分别为9.44%和5.51%。水菖蒲两种方法提取物对谷蠹、玉米象成虫均具较强触杀活性,并且对谷蠹成虫的触杀活性均明显强于其对玉米象成虫的触杀活性,其中,甲醇冷浸提取物比SFE-CO2提取物对谷蠹、玉米象成虫具有更强的触杀活性。对谷蠹成虫,甲醇冷浸提取物、SFE-CO2提取物处理4 d后的LD50分别为22.98μg/cm^2和33.94μg/cm^2;对玉米象成虫,其相应的LD50分别为159.89μg/cm^2和394.35μg/cm^2。     

甲酸对谷蠹乙酰胆碱酯酶及酯酶活性的影响

研究离体条件下甲酸对谷蠹酯酶和乙酰胆碱酯酶的抑制作用,结果表明较高浓度的甲酸对谷蠹酯酶和乙酰胆碱酯酶有抑制作用,但其抑制中浓度远远高于甲酸乙酯对谷蠹的致死中浓度,这说明甲酸对害虫酯酶和乙酰胆碱酯酶的抑制作用不是甲酸乙酯杀虫的主要机理。