胡瓜新小绥螨和尼氏真绥螨生物学特性比较研究

胡瓜新小绥螨Neoseiulus cucumeris和尼氏真绥螨Euseius nicholsi是重要的捕食性天敌,其中前者为引进种类,后者为本地种类。本文在室内25℃条件下,以粉螨为食料饲养胡瓜新小绥螨,以二斑叶螨为食料饲养尼氏真绥螨,组建生殖率表,结果表明：胡瓜新小绥螨的产卵量（平均36.35±5.56粒/雌）、內禀增长率（rm=0.0942）、周限增长率（λ=1.0988）均高于尼氏真绥螨的平均产卵量29.78±3.11粒/雌、内禀增长率rm=0.0827、周限增长率λ=1.0863,且种群倍增时间（t=7.35 d）也较尼氏真绥螨（t=8.38 d）短。通过各参数的比较,在恒温25℃条件下,胡瓜新小绥螨具有较大的生殖潜力。在以桔全爪螨为食料,进行混合饲养时,两种捕食螨的种群增长均受到抑制,而尼氏真绥螨受到的抑制更明显。说明胡瓜新小绥螨竞争力强于尼氏真绥螨。     

丁氟螨酯对二斑叶螨生长发育的影响

【目的】丁氟螨酯是一种新型酰基乙腈类非内吸性杀螨剂,对害螨的各个螨态都有很高活性,具有较高的应用价值。本文评价了丁氟螨酯对二斑叶螨生长发育的影响,以期为合理用药和二斑叶螨的综合防治提供理论依据。【方法】采用浸叶法测定丁氟螨酯对二斑叶螨成螨与卵的致死中浓度、雌成螨产卵量、各螨态存活率以及各发育历期的影响。【结果】经丁氟螨酯处理后,二斑叶螨日均产卵量和总产卵量下降,各螨态发育历期延长;LC₇₀、LC₅₀、LC₃₀剂量处理二斑叶螨雌成螨后,每雌日均产卵量为(2.09±0.17)、(3.02±0.22)、(3.39±0.13)粒,每雌总产卵量为(29.29±2.31)、(42.32±3.01)、(47.41±1.77)粒,与空白对照差异显著(P<0.05,df=3);不同剂量处理二斑叶螨卵后,各螨态发育历期的延长程度不同,但成功孵化的卵能完成发育历期,LC 70剂量延长卵历期至(4.45±0.07)d、前若螨历期至(2.75±0.04)d、后若螨历期至(2.61±0.05)d和总历期至(12.53±0.18)d,LC 50剂量延长前若螨历期至(2.52±0.08)d、后若螨历期至(2.67±0.09)d和总历期至(12.22±0.18)d,LC 30剂量延长前若螨历期至(2.45±0.06)d和总历期至(11.53±0.08)d,与空白对照差异显著(P<0.05,df=3)。【结论】丁氟螨酯能对二斑叶螨的生长发育产生明显影响,降低二斑叶螨的产卵能力,抑制卵孵化,延长发育历期,从而降低二斑叶螨种群的发育速率,对该螨的种群控制有积极意义。     

斯氏钝绥螨取食三种替代猎物的实验种群生命表

【目的】粉螨等储粮害螨易于获得和大量饲养,被广泛用作商业化大量繁殖捕食螨的替代猎物,为了明确常见粉螨等仓储害螨对斯氏钝绥螨Amblyseius swirskii (Athias-Henriot)的饲养潜力。【方法】室内分别对3种替代猎物(甜果螨Carpoglyphus lactis (L.)、腐食酪螨Tyrophagus putrescentiae (Schrank)、椭圆食粉螨AleuroglyphusovatusZachvatkin)饲养的斯氏钝绥螨生命表参数进行测定。【结果】斯氏钝绥螨取食3种替代猎物均能从卵发育至成螨并繁殖后代。取食甜果螨、腐食酪螨、椭圆食粉螨的斯氏钝绥螨雌螨的世代历期分别为6.43、9.20、6.30 d,平均每雌总产卵量分别为31.70、8.39和11.50粒,内禀增长率rm分别为0.191 8、0.055 0、0.116 2,周限增长率λ分别为1.211 4、1.056 5、1.123 2。此外,以甜果螨饲养的雌成螨寿命(39.02d)也是最长的。取食3种猎物的内禀增长率rm和周限增长率λ均以取食甜果螨的值为高。【结论】甜果螨是这3种猎物中最适于大量繁殖斯氏钝绥螨的猎物螨。     

迎春花花粉对伪钝绥螨生长发育和繁殖的影响

伪钝绥螨Amblyseius fallacis Garman是控制害螨的有效天敌,研究迎春花花粉和二斑叶螨Tetranychus urticaeKoch对伪钝绥螨生长发育和繁殖的影响,比较伪钝绥螨取食2种食料时各种参数的异同。结果表明,迎春花花粉可使伪钝绥螨正常生长发育并产卵,但发育时间较取食二斑叶螨的长,产卵量与取食二斑叶螨的相当。取食迎春花花粉时伪钝绥螨的内禀增长率、净增殖率和周限增长率均低于取食二斑叶螨时的值,世代平均周期较取食二斑叶螨略短,而种群倍增所需时间更长。由以上结果可知迎春花花粉可作为伪钝绥螨的替代或补充食料。     

不同食物对普通钝绥螨发育和繁殖的影响

分别用丝瓜花粉、桔全爪螨、朱砂叶螨、丝瓜花粉+桔全爪螨、丝瓜花粉+朱砂叶螨作为食物,测定普通钝绥螨(Amblyseius vulgaris)在不同食物条件下的发育历期、繁殖力、死亡率及子代性比,并组建其实验种群生命表。结果表明,普通钝绥螨取食有丝瓜花粉存在的食物比单独取食桔全爪螨或朱砂叶螨发育快,产卵量大,子代雌性比高。在前者情况下,普通钝绥螨种群的内禀增长力(r_m)为0.209—0.259,净增率(R_0)为18.918—35.771,由于雌成螨产卵期长,其平均世代时间(T)较长,为15.295—19.529天;在后者情况下,种群内禀增长力为0.165—0.191。净增率为7.091—17.113。由于雌成螨产卵期短,其平均世代历期亦较短,为11.50—14.23天。本研究还分别用丝瓜、党参、七里香、养麦、紫云英、玉米、兰花、栎树、西瓜、油菜、向日葵和益母草等12种植物的花粉饲养普通钝绥螨。结果表明,只有兰花花粉不能使该螨发育至成螨;后5种花粉虽能使其发育至成螨,但不能产卵;其余6种花粉能使其完成发育并产卵,其中丝瓜、党参和七里香花粉饲养效果较好。     

4种蔬菜对朱砂叶螨的抗性研究

４种供试蔬菜品种以对朱砂叶螨Ｔｅｔｒａｎｙｃｈｕｓｃｉｎｎａｂａｒｉｎｕｓ（Ｂｏｉｓｄｕｖａｌ）种群生长发育,繁殖及种群密度有明显增加,品种间存在的抗螨性差异,其中苦瓜抗螨性能,丝瓜,茄子,豇豆则表现在不同程度度的感螨性,朱砂叶螨能够取食苦瓜叶片,但发育历期延长,雌成螨寿命缩短,死亡率较高,而且在高苦瓜上不产卵,朱砂叶螨在豇豆,茄子,丝瓜上,发育历期短,雌成螨寿命长,产卵量大,死亡率低,Ｒ０,γｍ     

不同载体植物对二斑叶螨-深点食螨瓢虫生长发育和繁殖的影响

【目的】筛选出适宜二斑叶螨Tetranychus urticae Koch、深点食螨瓢虫Stethorus punctillum Weise生长发育和繁殖的载体植物,为深点食螨瓢虫的人工生产繁育提供技术支持。【方法】在(25±1)℃,光周期14L︰10D的条件下,测定二斑叶螨在花生Arachis hypogaea L.、豇豆Vigna unguiculata (L.) Walp、玉米Zea mays L.、辣椒Capsicum annuum L.、茄子Solanum melongena L.上的发育历期、产卵量;深点食螨瓢虫在这5种载体植物上的发育历期、产卵量、成虫获得率等。【结果】二斑叶螨和深点食螨瓢虫在不同植物上的生长发育和繁殖均存在显著差异,二斑叶螨在花生上的发育历期最短,为9.8d;在花生和豇豆上的平均产卵量最大,分别是117.2粒和116.0粒。深点食满瓢虫在5种植物上的发育历期由短到长依次为花生和豇豆(差异不显著)、玉米、辣椒、茄子;深点食螨瓢虫在花生、豇豆、玉米、辣椒、茄子上的产卵量依次为112.6粒、103.8粒、85.2粒、68.2粒、53.4粒。成虫获得率在花生、豇豆、玉米、辣椒、茄子上低依次是80.1%、70.3%、66.7%、9.7%、29.8%。【结论】在花生、豇豆、玉米、辣椒、茄子这5种供试植物中,花生是最适宜二斑叶螨和深点食螨瓢虫繁殖的植物。     

温湿度对腐食酪螨存活和繁殖的影响

研究了33种不同温湿度处理对腐食酪螨卵发育、孵化,成螨存活和繁殖的影响。结果表明：在15±1℃、20±1℃、25±1℃、30±1℃、35±1℃5种恒温下,相对湿度低于60％腐食酪螨几乎不能存活,高湿环境条件才有利于该种群正常繁衍。在适宜相对湿度范围,湿度与腐食酪螨成螨存活率关系显著,温度与腐食酪螨卵的发育历期、成螨日均产卵量关系极显著。     

猎物对巴氏钝绥螨生长发育和繁殖的影响

在(25±1)℃、90%RH以上、无光照实验条件下,以腐食酪螨和刺足根螨为猎物,研究了巴氏钝绥螨的生长发育和繁殖情况。结果表明,以腐食酪螨幼螨为猎物,巴氏钝绥螨可正常发育和繁殖,雌、雄成螨寿命分别为(34.250±1.361)和(23.950±1.606)d;以刺足根螨为猎物时,无法发育到成螨;成螨寿命明显缩短,雌、雄分别为(7.300±0.619)和(6.567±0.609)d,显著短于捕食腐食酪螨的巴氏钝绥螨,而且雌螨不能产卵。     

温度对微小花蝽生长发育和繁殖的影响

【目的】明确温度对微小花蝽Orius minutus生长发育和繁殖的影响。【方法】本研究以腐食酪螨Tyrophagus putresceniae为猎物,分别在5个恒温(15,20,25,30和35℃)条件下室内饲养,调查了温度对微小花蝽各虫态发育历期、存活率、成虫繁殖力以及种群参数的影响。【结果】在15~35℃范围内,各虫态平均发育历期均随温度升高而缩短,15℃下完成一个世代发育需要52.45 d,而35℃下仅需14.85 d。直线回归分析表明,微小花蝽世代发育起点温度为8.89℃,有效积温为359.20日·度。世代存活率和单雌平均产卵量均在25℃时最高,分别为17.07%和41.00粒。种群趋势指数在15℃和35℃下小于1,种群呈负增长;20~30℃下大于1,且25℃时最高,为3.92。净增殖率、内禀增长率和周限增长率均在25℃时最高,分别为3.32,0.04和1.04;种群世代周期以15℃时最长,为57.76 d,35℃时最短,为17.50 d。【结论】取食腐食酪螨的微小花蝽发育适宜温度范围为25~35℃,存活、繁殖和种群增长的最适温度均为25℃。这些结果为利用腐食酪螨人工饲养微小花蝽提供了基础参考数据。     

Survival,development and reproduction of Euseius finlandicus (Oudemans) (Acari: Phytoseiidae) fed on various kinds of food substances

Laboratory experiments were conducted to investigate the effect of diet on the biology of the phytoseiid mite, Euseius finlandicus (Oudemans). The predatory mite was able to develop and reproduce better when fed on the eriophyid mites, Aceria olivi (Zaher and Abou-Awad), Aceria dioscoridis (Soliman and Abou-Awad) and Cisaberoptus kenyae (Keifer). The developmental time of immature stages was the shortest when fed on motile stages of eriophyid mite species, followed by the spider mite, Tetranychus urticae Koch, and then pollen grains of Ricinus communis L., Phoenix dactylifera L. and Helianthus annuus L. Total egg production was highest when the predator fed on A. olivi, A. dioscoridis and C. kenyae recording at the rate of 51.0 50.0 and 43.84 eggs/female, respectively, but lowest on pollen grains, R. communis, P. dactylifera and H. annuus at the rate of 11.96, 5.3 and 2.0 eggs/female, respectively. But, the reproduction was nil on the tetranychid mite, T. urticae. Also, sex ratio of the progeny favoured females, when the predatory mite was reared on the eriophyid preys. E. finlandicus recorded the highest intrinsic rate of increase (r_m?=?0.31 females/female/day) when fed on A. dioscoridis, followed by (0.30 and 0.23 females/female/day) when fed on A. olivi and C. kenyae, respectively. In contrast, the lowest intrinsic rate of increase (r_m?=??0.31) was noted when fed on H. annuus pollen grains. The eriophyid mite, as a prey, recorded the shortest developmental time and highest oviposition rate of E. finlandicus.     

Effect of seven different pollens on bio-ecological parameters of the predatory mite Typhlodromus foenilis (Acari: Phytoseiidae)

Development, immature survival, reproduction, and life table parameters of the predatory mite Typhlodromus foenilis Oudemans were evaluated on seven different plant pollens (almond, apple, pear, cherry, apricot, plum, and walnut). Experiments were conducted in environmental chambers at 20 +/- 1 degrees C with 65 +/- 5% RH and a photoperiod of 16:8 (L:D). T. foenilis successfully completed its development on all pollen diets. Female mean developmental time from egg to adult emergence ranged from 11.3 +/- 0.12 to 14.28 +/- 0.23 d, whereas that of males was from 10.81 +/- 0.17 to 14.17 +/- 0.17 d. The average life span of adult females varied from 41.0 +/- 1.46 to 65.45 +/- 3.89 d, and total fecundity ranged from 11.78 +/- 0.65 to 39.09 +/- 2.38 eggs/female. The intrinsic rate of increase of T. foenilis was highest on almond pollen (r(m) = 0.104/d) and was the shortest on walnut pollen (r(m) = 0.055/d). The results show that this predatory mite develops well on all pollens, with almond and apricot pollens being of high nutritional value. This study provides further information for mass rearing of T. foenilis, and these findings are discussed in relevance with the establishment of this species in the field.     

Development of Iphiseiodes quadripilis (Banks) (Acari: Phytoseiidae) on pollen or mite diets and predation on Aculops pelekassi (Keifer) (Acari: Eriophyidae) in the laboratory

Development and reproduction of Iphiseiodes quadripilis (Banks) were evaluated on single food diets of pollen (Malephora crocea Jacquin [ice plant] or Quercus sp. [oak]), spider mites, [Eutetranychus banksi (McGregor) or Panonychus citri (McGregor) (Acari: Tetranychidae)], or the citrus rust mite Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae). Experiments were conducted in an environmental chamber at 28 degrees +/- 1 degrees C, 14:10 (L:D) daylength, and 45% RH. I. quadripilis completed development and laid viable eggs that subsequently hatched on diets of either ice plant or oak pollen or eggs and motile stages of E. banksi. P. citri was acceptable as prey, but survival of larvae to adults was only 36%, whereas survival on E. banksi, ice plant pollen, and oak pollen was 48, 60, and 68%, respectively. The webbing produced by P. citri seemed to inhibit foraging behavior of I. quadripilis larvae and nymphs. Larvae of I. quadripilis developed only to the second nymphal instar on a diet of P. oleivora alone or water alone. Starved I. quadripilis females and deutonymphs were observed preying on the pink citrus rust mite, Aculops pelekassi (Keifer) (Eriophyidae). During 4-min observation trials, two series of I. quadripilis fed on 1.8 +/- 0.47 and 3.5 +/- 0.45 A. pelekassi motile stages after being starved for 6 and 24 h, respectively. I. quadripilis females did not prey on P. oleivora in arenas containing both rust mite species.     

Feeding History Affects the Response of the Predatory Mite Typhlodromus Kerkirae (Acari: Phytoseiidae) to Volatiles of Plants Infested with Spider Mites

The response of adult females of the predatory mite Typhlodromus kerkirae (Acari: Phytoseiidae) to volatiles emitted from bean leaves infested with Tetranychus urticae (Acari: Tetranychidae) or from leaves of Oxalis corniculata infested with Petrobia harti (Acari: Tetranychidae) was studied in the laboratory using a Y-tube olfactometer. Typhlodromus kerkirae females reared from larvae through to adults on T. urticae and pollen of Vicia faba responded to volatiles of bean leaves infested with T. urticae, either when they had a choice between infested and non-infested bean leaves or between bean leaves infested with T. urticae and O. corniculata leaves infested with P. harti. However, they did not respond when they had been reared only on the carotenoid-deficient pollen of V. faba. Female T. kerkirae that had been reared from larva to the tenth day of adult life on T. urticae and subsequently fed for 1 week on V. faba pollen did not respond to volatiles of bean leaves infested with T. urticae. In contrast, those that had been reared on V. faba pollen to the tenth day of adult life and subsequently fed for 1 week on T. urticae responded to volatiles of infested bean leaves.     

Temperature and diet effects on immature development of predatory mite Typhlodromus athenas Swirski and Ragusa (Acari: Phyotseiidae)

Temperature and food quality both can influence growth rates and developmental time of herbivorous insects and mites. Typhlodromus athenas Swirski and Ragusa is an indigenous mite in the Mediterranean region and data on its temperature dependent development are lacking. In the current study, temperature-dependent development and survival of T. athenas immature stages were evaluated on eggs and all stages of Tetranychus urticae Koch, as well as on almond (Prunus amygdalis Batsch) pollen, under seven constant temperatures ranging from 15 to 35°C, 65% RH, and a photoperiod of 16:8 (L:D) h. On both diets survival was considerably high at all temperatures. The longest developmental period of immature stages was recorded at 15°C, whereas the shortest was at 30°C. Female immatures on almond pollen had shorter developmental time compared to that on twospotted spider mites. Food had a significant effect on female total developmental time at temperatures lower than 25°C. The lower developmental thresholds, estimated by a linear model, for egg-to-adult of females and males fed on pollen were 8.60 and 8.77°C, respectively, whereas on T. urticae they were 10.15 and 10.62°C, respectively. Higher values of tmin for total development were estimated by a nonlinear model (Lactin-2), and ranged from 10.21°C for both females and males on almond, to 11.07 for females and 10.78°C for males on prey. Moreover, this model estimated optimal and lethal temperatures accurately. The results of this study indicate that T. athenas appears better adapted to higher temperatures that occur in the Mediterranean region and may be a useful biological control agent.     

Effect of long-term feeding history on functional and numerical response of Neoseiulus californicus (Acari: Phytoseiidae)

The functional and numerical responses of the predatory mite Neoseiulus californicus to eggs and protonymphs of Tetranychus urticae were studied on excised strawberry leaflet discs under laboratory conditions (25 ± 1°C, 75–85% RH and 16L : 8D). Four strains of the phytoseiid were compared: three originated from a long-term mass-rearing with different food (T. urticae, Dermatophagoides farinae and Quercus spp. pollen) and under controlled conditions, while the fourth was directly collected from a natural environment and therefore considered a wild strain. The different nutritional histories affected the responses of N. californicus on tetranychids. On the whole, the wild strain gave better performance. When egg prey was administered this strain and the one mass-reared on two-spotted spider mites showed similar functional as well as numerical responses; on the contrary, when protonymphs were furnished, the wild strain did not differ from that mass-reared on pollen. The strain previously fed on house dust mites gave the worst performance and also showed the lowest percentages of females in the progeny. The functional responses obtained were predominantly type II curves. In all cases considered, no stored energy was allocated for reproduction and, with the exception of the wild strain on eggs, the prey was exploited less efficiently as the consumption increased. In spite of the differences evidenced in this experiment all strains were characterized by high predation and oviposition rates. Thus the results obtained suggest no drawbacks in the use of mass-reared N. californicus as biocontrol agents. © Rapid Science Ltd. 1998     

南非盲走螨实验种群的发育历期及生命表

在27℃条件下,以粗脚粉螨Acarus siro L.为饲料饲养观察南非盲走螨Typhlodromus(Anthoseius) transvaalensis(Nesbitt)的生长发育和繁殖情况,组建实验种群生命表。结果表明,南非盲走螨行孤雌生殖,卵、幼螨、前若螨、后若螨、成螨产卵前期各阶段发育历期分别为2.00,0.72,1.96,1.53,1.77d,完成1个世代发育需7.98d,雌成螨平均寿命14.82d、平均产卵量25.75粒,各种群生命参数分别为:净增殖率R0=25.01,世代平均周期T=13.71,内禀增长率rm=0.23,周限增长率λ=1.26,种群倍增所需日数t=2.95。采用小空间湿度控制法,测定不同湿度对南非盲走螨卵的孵化和成螨产卵的影响。结果表明,卵发育和孵化的最适湿度为75.0%~85.0%,96.0%的相对高湿度对成螨的产卵和存活均有不利影响。以橘全爪螨Panonychus citri McGregor不同螨态为猎物时,南非盲走螨对橘全爪螨幼螨的捕食量最大,日平均捕食量为5.40头,而对橘全爪螨雌成螨则几乎不取食。     

Effect of several different pollens on the bio-ecological parameters of the predatory mite Typhlodromus athenas Swirski and Ragusa (Acari: Phytoseiidae)

The development, survivorship, and reproduction of the predacious mite Typhlodromus athenas Swirski and Ragusa were studied in the laboratory by rearing the predator on nine different plant pollens [almond(Prunus amygdalis Batsch), apple (Malus domestica Borkh.), apricot (Prunus armeniaca L.), cherry (Prunus avium L.), pear (Pyrus communis L.), plum (Prunus domestica L.), walnut (Juglans regia L.), olive (Olea europaea L.), Typha sp.], and pollen collected from bee hives. All experiments were conducted in environmental chambers at 20 ± 1°C, 65% RH, and a photoperiod of 16:8 (L:D) h. Survival during immature development ranged from 81.1 to 96.0%. The shortest mean developmental time from egg to adult with respect to the range of pollen species was recorded for females and males fed on almond pollen (10.76 ± 0.18 and 10.45 ± 0.21 d, respectively), while the longest was on beehive pollen (26.97 ± 0.23 and 24.00 ± 0.25 d for females and males, respectively). Female longevity varied from 51.63 ± 5.52 d (olive pollen) to 102.81 ± 6.60 d (pear pollen), while fecundity ranged from 5.33 ± 2.35 eggs per female (beehive pollen) to 26.43 ± 1.73 eggs per female (almond pollen). The diet consisting of almond pollen resulted in the highest intrinsic rate of natural increase (r(m)) (1.00 d(-1)) and pollen collected from bee hives resulted in the lowest (0.013 d(-1)). These results showed that various pollen could favor the development of T. athenas, and also support the view that alternative food resources may play an important role in the field for sustaining and increasing the predator's population.     

Euseiusfinlandicus (Acari: Phytoseiidae) as a potential biocontrol agent against Tetranychus urticae (Acari: Tetranychidae): life history and feeding habits on three different types of food

Life history and reproductive parameters of the generalist predatory mite Euseius (Amblyseius) finlandicus (Oudemans) were studied in the laboratory at 25 +/- 1 degrees C, with a 16L:8D photoperiod and 60 +/- 15% RH, to investigate its response to different food sources: an eriophyid mite Aceria sp., tulip pollen Tulipa gesnerana L., and two-spotted spider mite Tetranychus urticae Koch. Total developmental time of the immature stages was the shortest on eriophyid mites, followed by pollen, and then spider mites. Fecundity was highest on pollen (43.69 eggs; 1.63 eggs/female/day), then eriophyid mites (39.73 eggs; 1.37 eggs/female/day) and lowest on spider mites (18.16 eggs; 0.80 eggs/female/day). Intrinsic rate of increase (Rm), net reproductive rate (Ro) and finite rate of increase (lambda) followed the same pattern [pollen (0.168, 27.96 and 1.183, respectively), eriophyid mites (0.153, 20.81 and 1.167), spider mites (0.110, 9.44 and 1.119)]. Mean generation time (days) was the shortest on pollen (19.90), followed by eriophyid mites (20.02), and then spider mites (20.59). Average spider mite larvae consumed by E. finlandicus during immature stages were 9.18 for males and 11.85 for females. Adult E. finlandicus females consumed an average of 166.38 spider mite protonymphs during adult stage compared to an average of 66.55 by males. The number of prey protonymphs consumed per day by females was highest in the oviposition period, lower in the pre-oviposition period and the lowest in the post-oviposition period. The eriophyid mite as a prey recorded the shortest developmental time, while pollen as food recorded the highest oviposition rate in E. finlandicus. The potential of this predator as a biocontrol agent against T. urticae is discussed.     

Acaricidal properties of spinosad against Tetranychus urticae and Panonychus ulmi (Acari: Tetranychidae)

Laboratory bioassays were conducted to characterize the activity of the insecticide spinosad against the twospotted spider mite, Tetranychus urticae Koch, and European red mite, Panonychus ulmi (Koch) (Acari: Tetranychidae). T. urticae females and larvae were individually placed on bean, Phaseolus vulgaris L. (Fabaceae), leaf disks treated with four rates of spinosad (25, 55, 121, and 266 ppm) and a water control. Significantly fewer T. urticae completed development on any spinosad rates (<15%) compared with the control (>85%), whereas spinosad exhibited no significant effects on P. ulmi development; 72.5 and 83.1% of P. ulmi completed development on apple (Malus pumila P. Mill, Rosaceae) leaf disks treated with 75 ppm spinosad and the control, respectively. T. urticae adult females placed on spinosad-treated disks had significantly higher mortality and lower oviposition rates compared with the water control; no significant mortality effects were observed until 3 d after placing adults on leaf disks. In choice tests where half of a bean leaf was treated with 55 ppm spinosad transversally or longitudinally, T. urticae females were repelled by spinosad and largely oviposited and fed on nonspinosad treated areas. Spinosad did not affect the behavior of P. ulmi females. When T. urticae females were released on potted bean plants (two-leaf stage) in which leaves received spinosad sprays on the adaxial or abaxial leaf surfaces, or complete spinosad coverage on one or two of the leaves, mite population increase lagged significantly behind those released on control plants. These results indicate that spinosad has significant acaricidal effects against T. urticae but not P. ulmi.