10种杀虫剂对梨小食心虫Grapholita molesta(Busck)卵的室内触杀效果

筛选对梨小食心虫卵具有高效触杀作用的药剂，旨在为该虫卵期的科学防治提供依据。采用浸渍法测定三唑磷、辛硫磷、哒螨啉、噻嗪酮、灭多威、除虫脲、丙溴磷、氟铃脲、仲丁威、丁醚脲10种药剂对梨小食心虫卵的室内触杀效果。结果表明，25％丁醚脲EC、20％氟铃脲WDG、20％哒螨灵wP和25％噻嗪酮SC的各稀释倍液的校正死亡率均低于0．1％，对梨小食心虫卵基本没有触杀效果；90％灭多威wP500倍液对梨小食心虫卵的触杀效果最高（死亡率99．33％），其次为100g／L丙溴磷乳油2000倍液处理（死亡率97．67％）；40％辛硫磷EC500和1000倍液、100g／L丙溴磷EC2500倍液、90％灭多威WP1000倍液的触杀效果均高于80％。综合考虑，建议使用90％灭多威WP的500～1000倍液、40％辛硫磷EC500～1000倍液或50％仲丁威EC500倍液进行梨小食心虫的卵期防治。

Molecular Characterization, Expression Patterns and Binding Properties of Two Pheromone-Binding Proteins from the Oriental Fruit Moth, Grapholita molesta(Busck)

Insect pheromone-binding proteins （PBPs） play important roles in transporting hydrophobic pheromone components across the sensillum lymph to the surface of olfactory receptors （ORs）. However, the PBPs of the oriental fruit moth, Grapholita molesta, an important destructive pest of stone fruits worldwide, are not well characterized. In this study, two new putative PBP genes, GmolPBP2 and GmolPBP3, were identiifed from G. molesta antennae. The deduced amino-acid sequences of these two putative PBP genes are characteristic of the odorant binding protein family, containing six conserved cysteine residues. The genomic DNA sequence of each gene contained two introns. However, the lengths and positions of the introns differed. RT-PCR analyses revealed that the two GmolPBP genes are only expressed in the antennae of female and male moths. Quantitative real-time PCR indicated that the transcription levels of GmolPBP2 are far greater than those of GmolPBP3 in both female and male antennae. GmolPBP3 showed higher transcription levels in female antennae than in male antennae, while GmolPBP2 showed similar transcription levels in both female and male antennae. The transcript levels of both genes were signiifcantly different in premating and post-coitum individuals, implying that mating affects the process of sex pheromone reception. To better understand the functions, two GmolPBPs were expressed in Escherichia coli, and the ligand binding assays were conducted. Results showed that GmolPBP2 has strong binding afifnities to two sex pheromone components, E8-12：Ac and Z8-12：Ac, as well as weaker binding afifnities to Z8-12：OH and 12：OH. GmolPBP2 also bound some ordinary odor molecules. However, the afifnity of GmolPBP3 to both sex pheromones and ordinary odor molecules was very weak. These results show that GmolPBP2 plays the main role in pheromone discrimination and recognition in the oriental fruit moth.

Analysis of Transfer Point of Grapholitha molesta Busck in Main Hosts in the Field

[Objective] The paper was to understand the selectivity and transitivity characteristics of Grapholitha molesta Busck in the course of host transfer.[Method] The damage time point of G.molesta was analyzed through sex pheromone trapping technique and reaction of resistance or susceptibility of different hosts.[Result] Along with the development of fruit tree organs,G.molesta appeared certain regular dynamics.During the flowering period of fruit trees,certain peaks of G.molesta were observed in pear orchard and peach orchard,and the average trap catches were182.8 and 208.6 moths,respectively.With the growth of new shoots,fruit expansion and ripening during the growth period of fruit trees,the trap catches and damage rate of peach trees were significantly higher than those of pear trees during new shoot stage,which were 151.8 and 118 moths,11.13% and 0.05%,respectively.There were significant differences in infected shoot rate.The trap catches in pear orchard reached the maximum at fruit ripening stage,which were 102.2,192.8,36 and 61.2 moths,respectively.There were significant difference in trap catches between pear orchard and peach orchard during fruit expansion stage and fruit ripening stage.[Conclusion] The study lays a foundation for accurately promoting effective prevention and control combining biological control and chemical control against G.molesta.

Selectivity Analysis of Grapholitha molesta(Busck) for Different Pear Varieties

Through analysis of trap catches and fruit decay rate of different pear varieties,it was found that there were significant differences in parasitization of Grapholitha molesta（ Busck） among different pear varieties. The trap catches of Huangguan pear was the highest; the fruit decay rate of Xueqing pear was extremely higher than those of other varieties; the trap catches of early red comice were significantly lower than those of other varieties,and no injured fruits were found.

甘肃省白银和张掖地区梨园梨小食心虫和桃小食心虫发生动态

在甘肃省白银和张掖地区梨园,利用三角形性诱捕器连续3年(2021年-2023年)监测了梨小食心虫Grapholita molesta(Busck)和桃小食心虫Carposina sasakii Matsumura种群动态。结果表明,该地区主要以梨小食心虫发生为主,一年发生3代和不完全4代;越冬代成虫约在4月上旬开始出现,第1代高峰期为5月中下旬至6月初,第2代高峰期为7月上中旬,第3代发生高峰期在8月底至9月中旬。不同地区不同年份年诱蛾总量差异较大,最高可达3835头/诱捕器,最低为412头/诱捕器。桃小食心虫在该地区1年发生2代,且发生量较少,全年诱虫总量在70头/诱捕器以下。通过对3个监测点3年数据的分析,初步掌握了梨小食心虫和桃小食心虫在甘肃省这两个地区的发生规律,为达到良好防控效果,应选择越冬代高峰期之前,即4月中旬进行第一次防治。

不同蜂卵比条件下松毛虫赤眼蜂对梨小食心虫卵的寄生效果

为了明确不同蜂卵比条件下松毛虫赤眼蜂对梨小食心虫卵的寄生效果,采用室内试验方法,研究了不同蜂卵比(1∶5、1∶10、1∶15、1∶20、1∶30)条件下松毛虫赤眼蜂对梨小食心虫卵的寄生率、寻找效应,以及松毛虫赤眼蜂后代羽化率的影响。结果表明:随着单蜂供卵比例的增加,松毛虫赤眼蜂对梨小食心虫卵的寄生率逐渐降低、寻找效应呈先增加后降低的变化,其中,蜂卵比为1∶5时寄生率最高,蜂卵比为1∶20时寻找效应最大,且与其他处理差异均达到了显著水平;松毛虫赤眼蜂后代羽化率逐渐增加,其中蜂卵比为1∶(5~15)时羽化率差异不显著。对不同蜂卵比处理下的寄生率、寻找效应和羽化率进行综合,认为蜂卵比为1∶(10~15)时,松毛虫赤眼蜂对梨小食心虫卵的寻找和寄生效果较好。研究结果为松毛虫赤眼蜂的田间应用提供了理论依据。

苹果蠹蛾和梨小食心虫迷向丝在核桃园中的使用模式

【目的】筛选核桃园中苹果蠹蛾和梨小食心虫最佳防治与迷向丝放置密度与高度。【方法】于2021~2022连续两年在核桃园设置不同悬挂密度(300、450、600根/hm^(2))和高度(6~8 m、8 m、6 m)的迷向丝,通过田间迷向干扰试验,测定不同悬挂密度和高度的迷向丝对苹果蠹蛾和梨小食心虫的防治效果。【结果】与对照相比,设置密度为300、450、600根/hm^(2)的苹果蠹蛾/梨小食心虫混合迷向丝和苹果蠹蛾、梨小食心虫迷向丝的迷向率和蛀果率之间存在显著差异(P<0.05),高密度处理的迷向丝迷向效果最好,且相同密度处理的各处理苹果蠹蛾/梨小食心虫混合迷向丝与苹果蠹蛾、梨小食心虫迷向丝迷向率和蛀果率之间无显著差异;与对照相比,迷向丝悬挂高度为6~8 m(双层)、8 m、6 m的迷向率和蛀果率之间存在显著差异(P<0.05),悬挂高度为8 m的迷向丝对苹果蠹蛾和梨小食心虫的迷向效果最佳,迷向率分别达到了96.41%、99.71%,防效达到了90.70%。【结论】核桃园苹果蠹蛾/梨小食心虫混合迷向丝最佳设置密度为450根/hm^(2),最佳悬挂高度为8 m为宜,大面积连片使用1年以上。

梨小食心虫对阿维菌素的抗性风险评估及其交互抗性

【目的】明确阿维菌素致死中浓度(LC50)连续处理对梨小食心虫(Grapholita molesta)的抗性风险及其交互抗性。【方法】在室内条件下,采用浸果法测定阿维菌素对梨小食心虫田间种群(F)初孵幼虫的LC50值;以F种群为基础,建立梨小食心虫对阿维菌素相对敏感品系(SS)、F种群连续6代接触LC50浓度阿维菌素的田间抗性品系(FR)和6代未接触阿维菌素的田间对照品系(FS),测定阿维菌素对不同品系梨小食心虫初孵幼虫的毒力,计算其抗性水平;测定高效氯氟氰菊酯、吡虫啉和氯虫苯甲酰胺对不同品系的毒力,分析不同品系与其交互抗性。【结果】田间种群对阿维菌素抗性倍数为4.608倍,敏感性降低;阿维菌素致死中浓度汰选2代后,梨小食心虫对阿维菌素抗性为低水平,汰选4代后升至中等水平,6代后升至20.304倍;未接触阿维菌素的梨小食心虫从第4代降为敏感,第6代时敏感性进一步恢复。抗性品系抗性现实遗传力h2=0.186,在致死率50%~90%选择压力下,梨小食心虫对阿维菌素抗性增加10倍,预计需汰选4~9代。汰选6代品系对高效氯氟氰菊酯抗性倍数为8.487倍,有交互抗性;对吡虫啉和氯虫苯甲酰胺无交互抗性。对照品系对高效氯氟氰菊酯、吡虫啉和氯虫苯甲酰胺均无交互抗性。【结论】梨小食心虫对阿维菌素存在快速产生抗性的风险,中抗品系与高效氯氟氰菊酯有交互抗性,低敏感品系与3种药剂均无交互抗性。田间使用阿维菌素时可通过间隔用药或与无交互抗性药剂轮换使用来减缓抗性发展。

我国防治梨小食心虫用农药登记现状

以“中国农药信息网”和“中国农药一点通”汇总的数据为基础,本文重点分析了我国防治梨小食心虫用农药登记情况,从产品数量、有效成分、剂型、毒性等方面展开了讨论。结果显示,用于防治梨小食心虫的农药在登记上存在用药短缺、复配农药和生物农药不足、产品同质化严重、剂型老化等问题。针对存在的问题给出了合理建议,以期为我国安全高效防治梨小食心虫提供参考。

梨小食心虫卵黄原蛋白基因的鉴定及表达分析

为明确重要果树害虫梨小食心虫(Grapholita molesta)卵黄原蛋白(Vitellogenin,Vg)基因功能及其生殖调控机制,为GmVg基因功能的深入研究奠定理论基础,克隆鉴定了梨小食心虫卵黄原蛋白基因(GmVg)并进行生物信息学分析,通过qRT-PCR分析GmVg在梨小食心虫不同发育时期、不同性别和不同组织的表达模式。结果表明,GmVg基因全长5 573 bp,开放阅读框(ORF)5 364 bp,编码1 787个氨基酸,信号肽长度为15个氨基酸,分子式为C_(9041)H_(14090)N_(2544)O_(2743)S_(57);氨基酸组成中丙氨酸(Ala)、谷氨酸(Gln)和丝氨酸(Ser)占比最大,分别为8.2%、7.9%和7.8%,酸性残基的数量(Asp+Glu)为187个,碱性残基的数量(Arg+Lys)为204个,预测蛋白质分子质量和等电点分别为204.1 ku和8.79,具有Vitellogenin-N、DUF1943和VWD共3个典型保守结构域。GmVg成虫期的表达量显著高于卵、幼虫和蛹期,且羽化后24 h时达到峰值。GmVg的表达具有性别特异性,在雄虫中表达量极低。GmVg在雌成虫头部、卵巢和脂肪体中的表达呈现组织特异性,其中脂肪体显著高表达,分别是头部和卵巢表达量的21.49倍和16.4倍。

梨小食心虫雄蛾的多次交配对雌蛾生殖力的影响

为明确梨小食心虫雄蛾的交配能力等生物学特性,正确评价梨小食心虫性信息素诱杀雄蛾的田间应用效果,本研究借助监控设备观察了梨小食心虫雄蛾与雌蛾的交配时间段、交配持续时间、雄蛾交配次数、雄蛾首次交配及末次交配日龄,研究了雄蛾日龄对交配率的影响,雄蛾交配次数对雌蛾产卵量及卵孵化率的影响。结果表明,梨小食心虫雄蛾能与多头雌蛾交配,且从1日龄至19日龄期间均能与雌蛾交配。随着雄蛾日龄的增加,其与雌蛾交配率降低,雄蛾交配次数的增加对雌蛾产卵量及卵孵化率没有显著影响。因此田间使用性信息素诱杀一定数量的雄蛾对降低后代种群数量有一定的作用,但只有在短时间内将雄蛾数量减少到一定范围内才可起到理想效果。

5种农药对梨小食心虫的室内毒力测定及田间药效评价

【目的】筛选出对梨小食心虫具有较强防效的农药。【方法】采用生测法和喷雾法分别测定5种农药对梨小食心虫的室内毒力和评价田间药效。【结果】5%甲维盐·虱螨脲对梨小食心虫的3龄幼虫的毒力最高,其LC 50值为4.12 mg/L,其次为10%高效氯氟氰菊酯、14%氯虫·高氯氟和10%氯虫苯甲酰胺,LC 50值分别为8.23、15.14和16.07 mg/L;25%甲维·灭幼脲毒力最低,LC 50值为40.65 mg/L;10%氯虫苯甲酰胺1000倍稀释液和5%甲维盐·虱螨脲2000倍稀释液对幼虫毒杀效果最好,处理24 h后,对幼虫校正死亡率均达到85%以上,72 h时达到100%。10%氯虫苯甲酰胺和5%甲维盐·虱螨脲的速效性最好,田间施药1 d后,防效能达到60%以上。施药后5 d,防效分别为87.72%和82.46%,显著高于其他农药。【结论】10%氯虫苯甲酰胺和5%甲维盐·虱螨脲对和田县桃树栽植区梨小食心虫幼虫具有较好的控制效果。

E8,E 10-12∶OH对梨小食心虫性诱剂的增效作用及其与信息素结合蛋白和普通气味结合蛋白的结合机制

【目的】(反,反)-8,10-十二碳二烯-1-醇[(8 E,10E)-dodecadien-1-ol,E8,E 10-12∶OH]是苹果蠹蛾Cydia pomonella的主要性信息素成分,对梨小食心虫Grapholita molesta性诱剂具有引诱增效作用。本研究旨在测定E8,E 10-12∶OH对梨小食心虫性诱剂的增效能力,确定主要结合E8,E 10-12∶OH的信息素结合蛋白(pheromone binding proteins,PBPs)和普通气味结合蛋白(general odorant binding proteins,GOBPs)。【方法】利用触角电位(electroantennogram,EAG)仪测定梨小食心虫雄成虫对0.002,0.02,0.2,2,20,200和2000μg E8,E 10-12∶OH激发的EAG反应;利用田间诱集试验测定E8,E 10-12∶OH对梨小食心虫性诱剂的增效能力;利用荧光竞争结合实验测定梨小食心虫信息素结合蛋白GmolPBP1,GmolPBP2和GmolPBP3及普通气味结合蛋白GmolGOBP1,GmolGOBP2和GmolGOBP3与E8,E 10-12∶OH的抑制常数K i;利用分子动力学模拟的方法预测GmolGOBP2结合E8,E 10-12∶OH的关键氨基酸;利用定点突变和荧光竞争结合实验验证GmolGOBP2结合E8,E 10-12∶OH的关键氨基酸残基及弱相互作用力。【结果】梨小食心虫雄成虫对E8,E 10-12∶OH表现出EAG反应,雄成虫对2000μg E8,E 10-12∶OH的EAG反应值最高[(0.57±0.14)mV]。在梨小食心虫性诱剂中添加200μg E8,E 10-12∶OH时,增效效果最佳,增效倍数达2.46倍。GmolGOBP2结合E8,E 10-12∶OH的能力最强[K i=(1.92±0.05)μmol/L],是结合E8,E 10-12∶OH的主要OBP。分子动力学模拟表明GmolGOBP2的Phe18,Ile100,Glu104,Val117和Phe124结合E8,E 10-12∶OH的自由能最低,分别为-1.18,-1.33,-3.34,-1.19和-1.58 kj/kg,预测是GmolGOBP2结合E8,E 10-12∶OH的重要位点,将以上5个残基定点突变为丙氨酸Ala后,突变体蛋白E104A和F124A失去了结合E8,E 10-12∶OH的能力,表明Glu104和Phe124是GmolGOBP2结合E8,E 10-12∶OH的关键氨基酸。【结论】E8,E 10-12∶OH是开发梨小食心虫高效性诱剂的理想增效剂,GmolGOBP2在梨小食心虫识别种间性信息素E8,E 10-12∶OH的过程中发挥着重要作用,Glu104和Phe124是GmolGOBP2结合E8,E 10-12∶OH的关键氨基酸残基。

梨小食心虫生物学特性及综合防控研究进展

梨小食心虫为世界性果树害虫,主要为害仁果类(如苹果、梨等)、核果类果树(如桃等)的新梢和果实。该虫虫体小、钻蛀性为害,隐蔽性强,发生代数多、世代重叠严重,生产上防治困难。而过度化学防治会导致“三R”问题严重,梨小食心虫发生为害已成为限制果树高质量绿色发展的主要因素之一。对梨小食心虫的生物学特性、综合防控措施(包括农业和物理防治,化学防治,生物防治、综合防治等)进行综述,以期为梨小食心虫的综合防控提供参考。

武汉地区砂梨园节肢动物识别图谱及两种主要发生害虫概况

【目的】为了解武汉地区砂梨园区中节肢动物的发生危害情况。【方法】采用人工鉴定的方式鉴别节肢动物所属类别,并将其取样拍照制成图谱。【结果】共调查到节肢动物种类有11目43科74种,两种主要发生害虫分别是梨瘿蚊和梨小食心虫,梨瘿蚊一年有3次发生高峰,分别在4月上旬、5月上旬和6月上旬,梨小食心虫一年有4次发生高峰,分别在5月下旬、6月下旬、8月中旬、9月中旬。【结论】武汉地区砂梨园区中节肢动物发生种类丰富,梨瘿蚊和梨小食心虫2种主要害虫是当地监测和防控的主要对象,应选用化学药剂或综合应用措施进行防治。

梨小食心虫在桃树和核桃间转移规律初步研究

为了掌握梨小食心虫Grapholita molesta在新疆和田县桃园和核桃园间的转移为害和种群动态变化规律,以期确定核桃园内梨小食心虫的最佳防治时间,同时在桃园和核桃园设立监测点,通过对梨小食心虫在桃园和核桃园间的发生动态监测以及在核桃园内产卵情况和蛀果率调查,明确了梨小食心虫在桃园和核桃园间的转移规律。研究发现梨小食心虫在和田县桃园1年发生5代,越冬代成虫于3月下旬开始出现,各代高峰期分别在4月上旬、5月中旬、6月下旬至7月上旬、7月下旬至8月上旬、9月上旬,以第1代和第2代发生为害严重,具有世代重叠现象。梨小食心虫在核桃园1年发生2代,成虫产卵于核桃果实和叶片,主要以幼虫为害果实。于6月下旬开始从桃园向核桃园转移,8月下旬又从核桃园转移至桃园,具有明显的寄主转移规律。7月初为核桃园内梨小食心虫的防治关键期。

桃小食心虫与梨小食心虫地理种群间快速耐热性差异

【目的】桃小食心虫Carposina sasakii与梨小食心虫Grapholita molesta是世界性果树害虫,气候变暖对其各自地理种群的发生与危害产生重要影响。本研究旨在明确桃小食心虫与梨小食心虫成虫地理种群间快速耐热性及其可塑性差异,以期为其预测预报与综合防控提供依据。【方法】通过测定基底条件(未经预处理)下与经过35℃预处理2 h的热锻炼条件下桃小食心虫与梨小食心虫成虫在恒温42.5℃下的击倒时间(knockdown time, KDT)与临界高温(critical thermal maximum, CTMax),系统比较了桃小食心虫吉林种群、郑州种群和实验室种群及梨小食心虫吉林种群、郑州种群、南昌种群和实验室种群等不同地理种群成虫的快速耐热性及其可塑性异同。【结果】桃小食心虫与梨小食心虫各地理种群成虫的KDT变化较为一致,两种食心虫各种群间与性别间的KDT均无显著差异,而热锻炼使桃小食心虫与梨小食心虫的KDT分别显著提高14.63和55.12 s,种群、性别和锻炼3个因子间两两交互或三者交互作用均不显著。桃小食心虫与梨小食心虫各自地理种群的成虫对CTMax反应差异较大,桃小食心虫成虫种群间CTMax差异显著,高低依次为吉林种群[(38.57±1.61)℃]、郑州种群[(37.60±1.32)℃]和实验室种群[(37.24±1.46)℃],锻炼对桃小食心虫成虫CTMax的影响显著,且与种群存在交互作用,主要体现在热锻炼使吉林和郑州种群的CTMax分别显著提高了2.05和1.34℃,而室内种群基底CTMax与热锻炼后无显著差异。梨小食心虫成虫种群间CTMax差异显著,从高到低依次为南昌种群[(39.20±1.81)℃]、吉林种群[(38.63±1.42)℃]、郑州种群[(38.27±1.32)℃]和实验室种群[(38.15±1.51)℃],热锻炼对梨小食心虫成虫CTMax的影响显著,且与种群存在交互作用,主要体现在热锻炼仅显著提高了郑州种群的CTMax [基底:(38.18±1.34)℃;热锻炼后:(39.17±0.60)℃],而对吉林种群、南昌种群和实验室种群的CTMax均无显著提高。性别因子、及其与种群或热锻炼的交互作用以及这3个因子三者交互作用分别对桃小食心虫和梨小食心虫成虫CTMax影响均不显著。【结论】与中部种群相比,桃小食心虫北方种群快速耐热性较强;而梨小食心虫南部、中部、北部种群间,南方种群快速耐热性较强;实验驯化均会降低两种食心虫的快速耐热性;锻炼会分别提高两种食心虫的快速耐热性,但不同种群间耐热可塑性不一致,上述结论可能由于物种间的热适应进化机制不同及地理种群间生存环境差异所致。厘清桃小食心虫与梨小食心虫地理种群间快速耐热性及其可塑性的异同,对气候变暖条件下昆虫热适应研究与果品安全生产具有重要意义。

Analysis of Host Selectivity and Taxis of Grapholita molesta in Different Peach Varieties

[Objective]The paper was to preliminarily determine the susceptible varieties of Grapholita molesta(Busck)by analyzing trap catches of peach trees at different ripening stages,new shoot damage rate and fruit damage rate at different development stages.[Method]Three traps were hanged in peach orchard of the same variety,with the interval of 30 m.The traps were fixed on ventilated and shaded branches for regular and fixed-point monitoring.Three trees were randomly selected from each variety to investigate the damage fruit rate and new shoot damage rate at east,south,west and north directions of each tree,and the number of infected fruits and damaged new shoots was recorded.[Result]There were obvious differences in taxis selection of G.molesta to different peach varieties,and the trap catches in the same variety varied among different periods.The damage caused by G.molesta in the same variety over the same period was different among different organs.The catch peak of late ripening peach 03-46-78 appeared on August 11.In summer shoot period,the trap catches of late ripening peach 03-46-78 were extremely higher than those of other varieties,and the damage rate of late ripening peach Jinyuan was extremely higher than that of other varieties.In autumn shoot period,the average trap catches of late ripening peach 03-46-78 were significantly higher than those of other varieties,and the damage rate of late ripening peach Jinyuan was significantly higher than that of other varieties.The investigation and analysis of different ripening stages of peach fruits showed that the damage rate of late ripening variety Ruiguang 39 was significantly higher than that of other varieties in the ripening stage.The trap catches of late ripening peach 03-46-78 were significantly higher than those of other varieties in the young fruit stage.The trap catches of late ripening peach 03-46-78 had significant difference with those of other varieties during fruit expansion stage.The trap catches of late ripening peach 03-46-78 had significant difference with that of other varieties during fruit ripening stage.[Conclusion]With the development of new shoots and the ripening of fruits,G.molesta appears different dynamic regularities in different organs of various varieties.The time point that G.molesta transfers with the development of fruit tree organs should be grasped to deeply analyze the physical and chemical properties of fruit trees during the growth period,so as to find out reasonable and effective prevention and control techniques for fruit farmers.

Host Range and Virulence of a Fungal Pathogen for Control of Giant Salvinia (<i>Salvinia molesta</i>)

A teleomorph of the fungus Botryosphaeria rhodina (Berkeley et Curtis) von Arx, (Br) was evaluated as a bioherbicide for control of giant salvinia (Salvinia molesta D.S. Mitchell) under greenhouse conditions and in small-scale field trials. We found that fungal mycelium was highly infective and could be rapidly produced (48+ h) in soy flour-cornmeal liquid media contained in shake flasks or fermenters. A dew period was not required to achieve infection and mortality of inoculated plants. A surfactant (Silwet L-77, a polyalkyleneoxide modified heptamethyl-trisiloxane) incorporated in the fungal formulation was required for Br to infect and kill plants. Infection and mortality occurred rapidly (within 48 h after treatment), and re-growth of treated plants did not occur. In replicated field trials, Br controlled giant salvinia ~95%. Br also infected other plants, such as common salvinia (S. minima Baker), and Azolla filiculoides Lam., as determined in ongoing host range research. However, no symptomatology was observed on several economically important crop species, such as rice (Oryza sativa L.), corn (Zea mays L.), and several woody species such as bald cypress (Taxodium distichum L.) and loblolly pine (Pinus taeda L.) occurring in areas where giant salvina occurs that would be subject to contact with releases of Br. These results suggest that this teleomorph of Botryosphaeria rhodina has potential as a bioherbicide for controlling this onerous aquatic weed.

宁南山区杏园三种食心虫种群发生动态

为掌握宁南山区杏园食心虫发生规律,2018年和2020年采用性诱监测方法对彭阳县杏园梨小食心虫、桃小食心虫和李小食心虫成虫种群动态进行了系统监测。结果表明,宁南山区杏园梨小食心虫成虫田间发生期为4月上旬至9月中旬,发生高峰分别为4月底至5月初、5月下旬初和6月中旬末至下旬初,7月上旬后零星发生,无明显峰期。不同坡向虫口数量分布呈现东坡>南坡>西坡,不同坡向的上、中、下坡位虫口数量均以中、下层坡位分布为主。桃小食心虫成虫发生期为5月中旬或下旬至8月下旬或9月初,发生高峰分别为6月上旬或中旬初和7月中旬或下旬;李小食心虫成虫发生期为5月上旬至9月上旬,发生高峰分别为6月上旬、7月上旬和8月上旬。宁南山区对杏园3种食心虫防治可以采取以农业防治为基础,优先采用理化诱杀和生防技术,大发生时加强药剂适期防治的综合防治策略。