贵州烟草蚜传病毒病（PVY、CMV）发生规律及其预测模型的初步研究

通过2002-2011年对贵州代表性烟区烟草蚜传病毒病(PVY、CMV)的系统调查与普查,分析了烟草蚜传病毒病发生程度与有翅蚜迁飞量及主要气象因子间的关系,初步了解了该病害的发生流行规律。并以有翅蚜迁飞量和关键气象指标为预报因子,应用DPS统计软件进行逐步回归分析,初步建立了烟草蚜传病毒病发生程度短期预测模型Y=44.168 7+1.106 9 X1-1.352 2 X4-0.403 9 X6-0.142 6 X11+0.023 5 X19-0.289 2 X20(其中,X1=移栽初期10d内日平均诱蚜量;X4=上年12月均温;X6=上年12月平均相对湿度;X11=2月降水量;X19=5月降水量;X20=5月雨日数),经显著性检验和预报验证,回归方程达极显著水平,回测准确率平均达89.04%,实报验证误差率为11.57%～13.88%,说明入选预报因子比较切合贵州实际,预测模型具有较大的实用价值。     

江汉平原小麦赤霉病发生程度的中期预测

小麦赤霉病的发生与流行严重影响小麦的产量与质量。笔者基于对2001—2019年江汉平原小麦赤霉病的发生等级(Y)、稻桩带菌率(X_1)以及江汉平原气象资料:气象因子4月上、中旬雨日(X_2)、4月上、中旬雨量(X_3)、4月下旬至5月上旬雨日(X_4)、4月下旬至5月上旬雨量(X_5),运用二次多项式逐步回归方法,引入对发生等级作用显著的气象因子,建立回归预测模型。气象预测模型为Y=26.769 7-0.093 4X_1-13.006 1X_2+0.374 6X_3+0.192 8X_5+0.001 3X_1*X_1+0.739 9X_2*X_2+0.000 9X_3*X_3-0.017 1X_4*X_4+0.023 9X_1*X_2-0.002 5X_1*X_5-0.042 5X_2*X_3+0.498 3X_2*X_4-0.021 8X_3*X_4+0.000 7X_3*X_5-0.022 2X_4*X_5(r=0.999 0,p=0.001 5)。研究结果可在江汉平原小麦赤霉病预测预报中运用,为其防治提供参考。     

济宁滨湖区东亚飞蝗夏蝗发生趋势的长期预测研究

为提高济宁滨湖区东亚飞蝗的长期预报准确率,用微机以近10年的资料中筛选出上年残蝗密度(X1)、9月份平均气温(X2)等预报因子,建立了东亚飞蝗夏蝗发生密度的预报数学模型:Y=-0.612962121 0.05671876964X1 0.04263729416X2;筛选出上年秋残蝗面积(X1)、10月份湖水位(X3)等预报因子,建立了夏蝗发生面积的预报数学模型:Y=10.03378675 0.6631445638X1-0.24734864468X3。以上预测模型经过资料验证和2007年应用,预报准确率较高。     

贵州省烟蚜抗药性监测

本文采用浸渍法测定了贵州省德江、长顺、麻江、湄潭、清镇和兴仁共6个烟区的烟蚜种群对6种杀虫剂的抗性水平,并进一步测定了贵州6烟区烟蚜种群对杀虫剂的交互抗性。结果表明:与相对敏感种群相比,湄潭烟区烟蚜种群对灭多威表现为低抗,其余5烟区烟蚜种群均处于低抗以下水平;长顺烟区烟蚜种群对阿维菌素表现为低抗,其余5烟区烟蚜种群均处于敏感水平;德江、湄潭和清镇烟区烟蚜对乐果表现为低抗,其余3烟区均处于敏感性下降阶段;6烟区烟蚜种群对啶虫脒、溴氰菊酯和吡虫啉均处于低抗以下水平。啶虫脒与乐果的交互率最高,达到77.46%,灭多威与吡虫啉的交互率最低,为30.11%。     

水稻白背飞虱主害代发生因子分析与发生量预测模型

运用浙江省天台县1971-2012 年测报历史资料进行了早稻与单季稻主害代白背飞虱发生关键因子分析,建立了回归预测模型。结果表明：影响早稻白背飞虱主害代发生的关键因子有：灯下初见期、上一代田间发生量、6月下旬发生率与灯下3～4代诱虫量;影响单季稻白背飞虱主害代发生量的关键因子有：上一代田间发生量与3～4代灯下诱虫量。逐步回归分析结果表明,早稻7月下旬白背飞虱发生量逐步回归方程Y1=5.050 3+0.146 1X4+0.251 7X5-0.326 2X8+0.437 6X9+0.301 3X10;单季稻8月上旬白背飞虱发生量逐步回归方程Y2=0.695 4+0.338 3X2+0.060 1X3-0.566 3X6-0.960 2X7+1.160 6X8+1.739 7X10,逐步回归方程可用于白背飞虱发生趋势的中短期预报。     

黔中地区小家鼠种群数量动态及预测预报模型

为了摸清小家鼠种群数量季节变化规律及其预测方法,采用夹夜法调查逐月捕获率,以捕获率为预测指标,建立预测预报模型,对1987~2005年贵州省息烽县小家鼠种群数量动态及种群数量进行分析预测。结果表明,小家鼠多年平均捕获率为3.26%±0.86%,在4月、7月、10月出现3次数量高峰期。根据历年小家鼠种群数量变动幅度及发生危害情况,制定了小家鼠种群数量分级标准。分析各月种群数量与数量高峰期4月、7月、10月种群密度的关系,建立了应用3月、6月、9月种群数量提前1个月预测数量高峰期4月、7月、10月种群密度的3个短期预测预报模型:Y1=1.5542X1-0.4258,Y2=1.3799X2+0.3213,Y3=1.1523X3+0.6890,以及应用4月种群数量预测当年平均种群密度的中期预测预报模型:Y4=0.4945X4+0.8187。经回测验证,数值和数量级预测值与实测值基本相符,数值预测平均吻合率为84.83%~93.94%,数量级预测平均吻合率为77.78%~100%。预测模型在2005年进行应用,结果较准确。     

稻瘟病预测模型及应用研究

整理分析广东省化州市20多年稻瘟病历史资料,成功地组建化州市叶瘟流行程度长期预测模型：X（k＋1）=1571212．511e^0.001259508k-1569234．511;穗瘟流行程度中期预测模型：D=0．866x1＋21．483x2＋13．194x3;穗瘟流行程度短期预测模型：y=1．0309＋2．0619x。1996—2006年连续在11．04万hm^2（次）稻田上进行预报应用,预报准确率达80％-100％,挽回稻谷3089．6万kg,净增加产值4526．7万元。同时减少用药面积8．31万hm^2（次）,共节约农药成本661．4万元,增收节支5188．1万元,取得了显著的经济、社会和生态效益,使防治稻瘟病达到新水平。     

小麦条锈病简易预报模式

存在大面积感病品种的条件下,小麦条锈病菌是否当地越冬决定春季显病迟早。发生程度受4月中旬-6月上旬气象因素的影响,5月中至下旬降雨量是影响条锈病发生程度的主要因子,其分级相关系数r=0.9254^**。本文选取条锈病菌越冬情况、4月中旬-5月上旬降雨量、5月中-下旬降雨量、6月上旬雨温系数4个因子,按条锈病发生发展的渐进规律,制定了简易预报模式,预报效果理想。     

蘑菇害螨发生程度预测模型的研究

采用判别分析法,根据浙江省富阳市1984～1995年12年的气象资料,经6个预报因子建立蘑菇害螨发生程度预测模型。经比较,筛选出上年7～8月份温湿系数,当年7～8月总雨日及温度指数3个因子,其组成的判别方程历史拟合率达917%。经两年的预测验证,结果与实际相吻合。     

蘑菇害螨发生程度预测模型的研究

采用判别分析法,根据浙江省富阳市1984～1995年12年的气象资料,经6个预报因子建立蘑菇害螨发生程度预测模型。经比较,筛选出上年7～8月份温湿系数,当年7～8月总雨日及温度指数3个因子,其组成的判别方程历史拟合率达917%。经两年的预测验证,结果与实际相吻合。     

新蚜虫疠霉感染致病蚜虫的空间分布特征及其理论抽样技术

[目的]探明新蚜虫疠霉的空间分布特点,为进一步研究蚜虫新蚜虫疠霉病害流行规律及田间释放病原菌防治桃蚜提供依据.[方法]调查甘蓝田新蚜虫疠霉感染致病桃蚜密度,采用Taylor幂法与Iwao回归法分析新蚜虫疠霉的空间分布特征.[结果]新蚜虫疠霉在甘蓝田呈聚集分布中的负二项分布,公共K值为2.87.Iwao直线回归方程拟合式为(m*)=0.12+1.36 m(R=0.99),Taylor幂公式为lg(v)=0.35+1.69 lgm (R=0.96).在不同季节,其空间分布的拥挤度差异显著(F=5.34,p＜0.01),7-9月平均拥挤度最高,而1-3月和10-12月最低.精度分别为0.1、0.2、0.3和0.5时的理论抽样数公式分别为n=430.26/x+138.30、n=107.56/x+34.57、n=47.81/x+15.37和n=17.21/x+5.53.当被新蚜虫疠霉感染罹病桃蚜密度较低,即低于每样方5头时,以模型n=17.21/x+5.53较为适宜,在较高密度,即每样方10头/株以上时,以模型n=107.56/x+34.57较宜.[结论]新蚜虫疠霉在甘蓝田均呈聚集分布中的负二项分布,聚集原因是新蚜虫疠霉生物学特性和环境因素.在6-8月,对该菌侵染蚜虫的总体理论抽样以抽查20株左右样方为宜,而在其他季节,抽查30株左右样方为宜.     

地丁草提取物对桃蚜的生物活性

以地丁草的全草为试材,在室内测定了不同提取方法和不同溶剂提取的地丁草提取物对桃蚜的生物活性。结果表明:不同提取方法和不同溶剂的提取物对桃蚜的毒力有显著差异。组合中以石油醚为溶剂的地丁草索氏提取物对桃蚜触杀活性最高,在浓度为100 g/L时,12、24、48 h的校正死亡率分别达80.00%、96.67%、98.33%,24 h的致死中浓度LC50达22.50 g/L;忌避作用试验表明,处理24、48、72 h后,地丁草索氏提取物对桃蚜的忌避率分别为88.75%、83.33%、83.33%。表明以石油醚为溶剂的地丁草索氏提取物对桃蚜有较高的触杀和忌避活性。     

蚜茧蜂对麦蚜控制作用的初步研究

本文应用二次通用旋转组合设计的方法进行了蚜茧蜂对麦蚜寄生能力的研究,得出了蚜茧蜂的寄生量模型：Ｙ＝９１．４０＋４３．６２Ｘ１＋２０．２７Ｘ２＋７．２５Ｘ１Ｘ２－１６．８３Ｘ１＾２＋３．４３Ｘ２＾２。并对模型进行了分析,表明对总寄生量的影响因素中麦蚜密度的大小大于蚜茧蜂本身密度的大小。在试验密度范围内,蚜虫和蚜茧蜂干扰作用不明显,且有相互促进的作用,但增加速度相同。     

杭州郊区菜蚜寄生蜂初步调查

1985～1986年,在杭州东郊系统调查了13块地5种十字花科蔬菜上蚜虫的寄生性天敌和被寄生率。共发现原寄生蜂两种,即菜小脉蚜茧蜂和烟蚜茧蜂,前者寄生于桃蚜和萝卜蚜,后者仅寄生于桃蚜,寄生率大多在0～3％,很少超过10％,在蚜虫数量上升阶段寄生率一般呈下降趋势,只有在蚜虫数量迅速下降阶段才明显上升,故蚜虫数量变化受寄生蜂影响不大。共发现重寄生蜂5种,重寄生率平均约为50％,高时接近100％。表明重寄生蜂在一定程度上影响了蚜茧蜂对蚜虫的控制效能。     

烟蚜防治指标研究

1991—1992年在湖南零陵对烤烟品种K326进行了烟蚜行动阈值的研究。设置了株蚜量0、5、10、20、50、100及200头7种不同防治标准作为试验处理,重复3次,共21个小区,每小区植烟40株,每隔2天调查1次,如某小区平均株蚜量等于或大于其防治标准时,即喷施1:1000的40％乐果乳油,直至平均蚜量低于防治标准为止。结果表明,在每隔2天调查1次的情况下,行动阈值为平均蚜量20头/株。分别对各处理的烟叶进行采收、烘烤、称重、评级及计算产值,结果得出经济阈值为平均蚜量100.69头/日/株。分析表明,两种阈值本质上一致。     

农药常用有机溶剂对烟蚜、棉蚜和大豆蚜定居行为的影响

实验室内研究了10种常用有机溶剂对烟蚜Myzus persicae、棉蚜Aphis gossypii、大豆蚜Aphis glycines定居行为的影响及蚜虫的行为反应。结果显示,3种蚜虫对供试有机溶剂具有相似的行为反应。在1~10 μL剂量范围下,乙醇、乙二醇、乙酸乙酯、二甲基甲酰胺和丙酮对3种蚜虫的定居行为有轻度的影响,但苯、二甲苯、己烷、石油醚和乙醚对蚜虫的定居行为有显著的影响。在适宜剂量下,3种蚜虫对苯和二甲苯的移动率皆超过30%,并伴随剧烈的行为反应。此外,棉蚜、烟蚜对己烷与石油醚反应的移动率分别达到44.27%、46.45%和49.90%、52.58%。     

Differential aphicidal effects of chitinase inhibitors on the polyphagous homopteran Myzus persicae (Sulzer)

Four chitinase inhibitors, cyclo-(Proline-Tyrosine), cyclo-(Histidine-Proline), allosamidin and psammaplin A, were selected for in vitro feeding experiments with the peach-potato aphid, Myzus persicae (Sulzer), under controlled photoperiod and temperature conditions. Artificial diets were used to provide chitinase inhibitors at 10, 50 and 100 microg mL(-1) to M. persicae. Except for cyclo-(Proline-Tyrosine), which did not modify aphid demographic parameters, chitinase inhibitors induced differential aphicidal effects on M. persicae. At all doses, cyclo-(Histidine-Proline) induced significant effects affecting daily fecundity, intrinsic rate of natural increase (r(m)) and doubling time of population. When compared with the control diet, allosamidin decreased nymph survival and daily fecundity, increasing the doubling time of population from 1 to 1.5 days. Psammaplin A was the most toxic inhibitor when delivered via artificial diet, as it induced the death of all aphids reared at 50 and 100 microg mL(-1). The results demonstrate the potential use of chitinase inhibitors as aphid management tools.     

Transmission efficiency of Papaya ringspot virus by three aphid species

The transmission efficiency of Papaya ringspot virus (PRSV) by three aphid vectors (i.e., Aphis gossypii, A. craccivora, and Myzus persicae) was studied. Efficiency was measured by single-aphid inoculation, group inoculation (using five aphids), duration of virus retention, and the number of plants following a single acquisition access period (AAP) to which the aphids could successfully transmit the virus. Single-aphid inoculation studies indicated that M. persicae (56%) and A. gossypii (53%) were significantly more efficient in transmitting PRSV than A. craccivora (38%). Further, in the former two species, the time required for initiation of the first probe on the inoculation test plant was significantly shorter compared to A. craccivora. PRSV transmission efficiency was 100% in all three species when a group of five aphids were used per plant. There was a perceptible decline in transmission efficiency as the sequestration period increased, although M. persicae successfully transmitted PRSV after 30 min of sequestration. A simple leaf-disk assay technique was employed for evaluating the transmission efficiency of three species of aphids. The results of leaf-disk assays also indicated that A. gossypii (48%) and M. persicae (56%) were more efficient PRSV vectors than A. craccivora. Using leaf-disk assays, the ability of individual aphids to inoculate PRSV serially to a number of plants was studied. Following a single AAP on an infected leaf, M. persicae was more efficient than the other two species with 52.5% transmission after the first inoculation access period (IAP). However, its inoculation efficiency significantly decreased with the second and subsequent IAPs. A. gossypii was able to transmit PRSV sequentially up to four successive leaf disks, but with significantly declining efficiency. Since A. gossypii is reported to be the numerically dominant vector in south India in addition to being a more efficient vector capable of inoculating PRSV to multiple plants, it should be the target vector for control strategies.     

Comparative analysis of neonicotinoid binding to insect membranes: II. An unusual high affinity site for [3H]thiamethoxam in Myzus persicae and Aphis craccivora

Neonicotinoids represent a class of insect-selective ligands of nicotinic acetylcholine receptors. Imidacloprid, the first commercially used neonicotinoid insecticide, has been studied on neuronal preparations from many insects to date. Here we report first intrinsic binding data of thiamethoxam, using membranes from Myzus persicae Sulzer and Aphis craccivora Koch. In both aphids, specific binding of [3H]thiamethoxam was sensitive to temperature, while the absolute level of non-specific binding was not affected. In M persicae, binding capacity (Bmax) for [3H]thiamethoxam was ca 450 fmol mg(-1) of protein at 22 degrees C and ca 700 fmol mg(-1) of protein at 2 degrees C. The negative effect of increased temperature was reversible and hence not due to some destructive process. The affinity for [3H]thiamethoxam was less affected by temperature: Kd was ca 11 nM at 2 degrees C and ca 15 nM at 22 degrees C. The membranes also lost binding sites for [3H]thiamethoxam during prolonged storage at room temperature, and upon freezing and thawing. In A craccivora, [3H]thiamethoxam was bound with a capacity of ca 1000 fmol mg(-1) protein and an affinity of ca 90 nM, as measured at 2 degrees C. Overall, the in vitro temperature sensitivity of [3H]thiamethoxam binding was in obvious contrast to the behaviour of [3H]imidacloprid studied in parallel. Moreover, the binding of [3H]thiamethoxam was inhibited by imidacloprid in a non-competitive mode, as shown with M persicae. In our view, these differences demonstrate that thiamethoxam and imidacloprid, which represent different structural sub-classes of neonicotinoids, do not share the same binding site or mode. This holds also for other neonicotinoids, as we report in a companion article.     

Correlated responses to neonicotinoid insecticides in clones of the peach-potato aphid, Myzus persicae (Hemiptera: Aphididae)

BACKGROUND: Although there are still no confirmed reports of strong resistance to neonicotinoid insecticides in aphids, the peach-potato aphid (Myzus persicae Sulzer) shows variation in response, with some clones exhibiting up to tenfold resistance to imidacloprid. Five clones varying in response to imidacloprid were tested with four other neonicotinoid molecules to investigate the extent of cross-resistance.RESULTS: All four compounds-thiamethoxam, thiacloprid, clothianidin and dinotefuran-were cross-resisted, with ED(50) values ranked in the same order as for imidacloprid. Resistance factors ranged up to 11 for imidacloprid, 18 for thiamethoxam, 13 for thiacloprid, 100 for clothianidin and 6 for dinotefuran.CONCLUSION: This variation in response does not appear to be sufficient to compromise the field performance of neonicotinoids aimed at controlling aphids. However, it highlights the need for careful vigilance and stewardship in all M. persicae populations, and a need to consider neonicotinoids as a single cross-resisted group for management purposes.