The effect of the weaver ant,Oecophylla smaragdina (Hymenoptera: Formicidae), on the mango seed weevil,Sternochetus mangiferae (Coleoptera: Curculionidae), in mango orchards in the Northern Territory of Australia

Abstract

The mango seed weevil, Sternochetus mangiferae (Fabricius), is one of the major mango insect pests in northern Australia. A reasonable level of control can be obtained with insecticide sprays together with orchard sanitation, but the only option available for organic growers is the latter. Weaver ants, Oecophylla smaragdina (Fabricius), are effective in controlling the main insect pests in citrus, cashew and mango orchards. To determine whether weaver ants, which are usually abundant in non-sprayed mango orchards, have the potential to control the mango seed weevil, field experiments together with regular monitoring programmes at six orchards in the Northern Territory of Australia were conducted from 2001 to 2003. Data from two conventional orchards showed that the treatment with weaver ants plus soft chemicals produced lower levels of downgraded fruits (<0.5%) compared to the treatment with chemical insecticides (1.4 – 2.1%). In three organic or insecticide-free orchards, fruits were much less damaged on trees with weaver ants (<1%) than on trees without the ants (2.5 – 15.7%). In the sixth orchard, that had much higher mango seed weevil populations than the others, levels of downgraded fruits were lower on trees with abundant weaver ants than on trees with fewer weaver ants. We conclude that weaver ants are efficient biocontrol agents of the mango seed weevil, and that for successful control of the pest it is important both to maintain the ants at high levels and to destroy excess fruits.     

柑橘木虱防控药剂筛选及矿物油对其增效作用评价

为了筛选柑橘木虱高效防控药剂,提高药剂防治效果,本文探索了 10种杀虫剂对柑橘木虱的田间防效及矿物油对杀虫剂的增效作用.结果表明:对柑橘木虱成虫,22％噻虫·高氯氟悬乳剂(SE)、70％吡虫啉可湿性粉剂(WP)、6％联菊·啶虫脒微乳剂(ME)和5％高效氯氟氰菊酯ME的速效性好,药后1 d防效94.61％～100％;22...     

Resistance to chlorpyrifos and lambda-cyhalothrin along with detoxifying enzyme activities in field-collected female populations of European red mite

The levels of susceptibility of populations of the European red mite Panonychus ulmi (Koch) (Acarina: Tetranychidae) collected from apple orchards in the Bursa region of Turkey to the insecticides chlorpyrifos and lambda-cyhalothrin, were determined by a petri leaf disk—Potter spray tower method. When compared with the susceptible population, resistance ratios at the LC₅₀ level ranged from 6.0- to 35.6-fold, and from 0.7- to 5.7-fold for chlorpyrifos and lambda-cyhalothrin, respectively. Kinetic parameters of general esterase activity with α-naphthyl acetate as substrate indicated that an increased activity was present in the resistant populations compared with the susceptible populations. In these strains, 1.5- and 2.2-fold higher Glutathione S-transferase (GST) activity was also detected with the substrate 1-chloro-2,4-dinitrobenzene. General esterase activity gel profiles of these populations were studied by native polyacrylamide gel electrophoresis, but no relationship between resistance ratios and band patterns was detected. The results of this study document a decreased efficacy of chlorpyrifos and lambda-cyhalothrin in field populations of P. ulmi in Turkey, possibly linked to altered activities of esterases and GST.     

Laboratory shelf-life of oil-formulated conidia of the locust and grasshopper fungal pathogen Metarhizium flavoviridae Gams & Rozsypal,in mixtures with the pyrethroid insecticide lambda-cyhalothrin

The addition of 20 ppm lambda-cyhalothrin pyrethroid insecticide to Metarhizium flavoviridae (Fungi: Deuteromycetes) dry conidia in oil kept germination above 80% for 2 and 12 months at temperatures of approximately 30 and 8°C respectively. At 30°C, conidia in oil alone maintained viability for only a few weeks, but this was doubled at 8°C. Even dry conidia retained good viability for only 5 months at the higher temperature. The extended viability of conidia given by adding the pyrethroid to the oil formulation is regarded as very valuable for areas where the fungus is to be used against locusts and grasshoppers.     

A malathion-tolerant strain of the spiderChiracanthium mildei and its response to chlorpyrifos

Chiracanthium mildei L. Koch (Araneae: Clubionidae) spiders, from two populations, were collected and reared in the laboratory. One originated from a citrus grove at Kibbutz Afeq and the other from an experimental cotton field at the Newe Ya’ar Experiment Station. Laboratory evaluation indicated that the Afeq strain was more tolerant to malathion than the Newe Ya’ar strain (resistance factor of x3.3). When spiders of the Afeq strain were exposed to chlorypyrifos (Dursban) and malathion residues, chlorpyrifos was much more toxic.     

Efficacy of chemical plant protection products on potato in Ukraine1

The principal potato pests controlled with plant protection products in Ukraine are Leptinotarsa decemlineata and Phytophthora infestons. Results are presented of trials of insecticides and fungicides against these pests. As a result, Sumi-alfa 5% EC (a.s. esfenvalerate), Karate water-soluble granules (a.s. lambda-cyhalothrin) and Betabytroid 2.5% EC (a.s. beta-cyfluthrin) were recommended for full-scale testing against Colorado beetle in Ukraine. Sul'fokarbation and EKhR 19517 were recommended for full-scale testing against potato blight.     

防治桃小食心虫越冬幼虫的有效药剂及其降解动态

研究树下土表施药防治桃小食心虫越冬幼虫的取代药剂。用毒土法测定了分属4类的13种药剂对桃小食心虫越冬幼虫的触杀毒力,其结果以毒死蜱、三唑磷、高效氯氟氰菊酯、甲基对硫磷和辛硫磷毒力较高,LC_(90)值依次为18．38、22．48、35．95、47．63及49．57 mg·kg~(-1),甲氰菊酯、丙溴磷、阿维菌素、甲胺基阿维菌素、氰戊菊酯、马拉硫磷、丙硫克百威和丁硫克百威LC_(90)值处于77．11～205．86mg·kg~(-1)之间。用高效液相色谱法测定了毒力较高的毒死蜱、三唑磷、高效氯氟氰菊酯以及阿维菌素在土壤中的降解动态,半衰期分别为8．28、11．37、10．17及19．70天。欲达30天的有效控制期,按LC_(90)值计算,这4种药剂在土壤中的初施浓度应分别为226．36、139．90、278．03及346．81mg·kg~(-1)。从药剂毒力、降解速率、相同控制期所需剂量及应用成本综合评价,毒死蜱、三唑磷具有较高的应用价值。     

稻螟赤眼蜂蛹期接触农药对其成蜂搜寻和寄生能力的影响

稻螟赤眼蜂Trichogramma japonicum是稻田中鳞翅目害虫重要的卵期寄生型天敌,为了规范稻螟赤眼蜂放蜂期农药的安全使用,利用卵卡浸渍法处理蛹期稻螟赤眼蜂,通过稻螟赤眼蜂室内飞行装置和单雌寄生法评估了蛹期5种非鳞翅目害虫靶标农药井冈霉素、三唑酮、吡蚜酮、印楝素、毒死蜱对稻螟赤眼蜂成蜂搜寻和寄生能力的影响。搜寻能力结果显示,在毒死蜱处理后稻螟赤眼蜂失去搜寻能力,三唑酮、吡蚜酮和印楝素处理对稻螟赤眼蜂的搜索行为无影响,但井冈霉素处理下稻螟赤眼蜂的飞行蜂比例为48.1%,显著低于对照处理的74.7%。寄生能力结果显示,毒死蜱处理对稻螟赤眼蜂高毒,能使稻螟赤眼蜂失去寄生能力;印楝素处理对稻螟赤眼蜂的寄生力和子代羽化率无显著影响;井冈霉素、三唑酮和吡蚜酮处理下稻螟赤眼蜂的寄生力分别为22.2、25.3和24.7,显著低于对照的27.4、31.1和29.6,但对子代羽化率无显著作用。表明印楝素对稻螟赤眼蜂安全,可以推广使用;井冈霉素、三唑酮和吡蚜酮对稻螟赤眼蜂的搜索能力(仅井冈霉素)和寄生能力有显著的削弱作用,应谨慎使用;毒死蜱对稻螟赤眼蜂高毒,在稻螟赤眼蜂放蜂期应该禁用。     

Entomological Problems of Agriculture in Bangladesh

Abstract

The location and climate of Bangladesh are described, together with the crops grown and organisations related to agriculture. The entomological problems of the main crops; rice, jute, sugarcane, and fruit crops such as mango, citrus, litchi, jack fruit, guava, banana, coconut and plum are presented. Some serious pests; aphids, epilachna beetles, ants, fruit flies, termites, cutworm and mealybugs are reviewed.     

毒死蜱微球和乳油在水中的消解动态及其对白纹伊蚊幼虫的毒力

室内条件下,研究了不同浓度毒死蜱微球和毒死蜱乳油在水中的消解动态及其对白纹伊蚊Aedes albopictus 3龄幼虫的持续毒杀作用。结果表明:毒死蜱微球在水中的消解速率比乳油慢,半 衰期比乳油的长,高浓度微球和乳油的消解半衰期均长于低浓度下的消解半衰期。有效成分为1.2、 12和24 mg/L的毒死蜱微球和毒死蜱乳油在水中的消解半衰期分别为(19.4±2.1) d、(27.8±1.6) d、(31.0±1.7) d和(12.8±1.0) d、(16.1±0.9) d、(19.7±1.1) d;毒死蜱微球对白纹伊蚊3龄幼虫的毒杀作用强于乳油且持效期长,1.2 mg/L的毒死蜱微球水解85 d后处理白纹伊蚊3龄幼虫的死亡率高达76.6%,高于相同浓度、相同条件乳油的处理(53.3%),具有良好的持效性。     

Comparative toxicity of several insecticides to eggs,larvae and adults of the Egyptian cottonworm,Spodoptera littoralis,in laboratory trials

Insecticides commonly used in cotton fields in Israel against lepidopterous pests were tested against eggs, as well as against 2nd-instar larvae and adults raised from eggs ofSpodoptera littoralis (Boisduval) collected in cotton fields in the Bet She’an Valley. Methomyl, chlorpyrifos, methidathion, monocrotophos, ethyl parathion, and methyl parathion were effective against eggs even at low doses, profenofos and phosfolan were less active, and azinphos-methyl was ineffective. The doses needed for 90% kill (LD ₉₀ ) of the 2nd-instar larvae were 8.5, 35, 280, 1300 and 3400 g a.i./1000 m ² for chlorpyrifos, methomyl, profenofos, methyl parathion and ethyl parathion, respectively; monocrotophos was inactive against 2nd-instar larvae even at relatively high doses. The LD ₉₀ of adults was reached with 16, 32, 1700 and 6100 ga.i./l000 m² of chlorpyrifos, methomyl, ethyl parathion and profenofos, respectively. Only chlorpyrifos and methomyl gave successful control of all three stages of the insect tested, at doses close to those generally used with aerial applications.     

河南信阳、漯河黏虫种群对6种杀虫剂的敏感性

采用浸叶法测定了信阳和漯河两地黏虫种群对甲氨基阿维菌素苯甲酸盐(甲维盐)和氯虫苯甲酰胺等6种杀虫剂的敏感性。结果表明:信阳种群对6种药剂的敏感性由高到低依次为:甲维盐、氯虫苯甲酰胺、辛硫磷、高效氯氰菊酯、毒死蜱、高效氯氟氰菊酯,LC50分别为:0.035、0.230、3.566、3.716、5.025、13.315 mg/L;漯河种群的敏感性由高到低依次为:甲维盐、氯虫苯甲酰胺、毒死蜱、辛硫磷、高效氯氰菊酯、高效氯氟氰菊酯,LC50分别为:0.053、0.734、3.081、3.413、13.570、25.067 mg/L。以毒死蜱为标准药剂,甲维盐对信阳和漯河3龄黏虫幼虫都表现出极高的活性,相对毒力指数分别达到143.571和58.132。     

The problem of Pitymys voles in orchards in central and southern Italy1

Voles of the genus Pitymys have in recent years caused serious damage in orchards (apple, citrus) in central and southern Italy. They gnaw the roots and base of the trunk of young and mature trees, killing them in a few days. The outbreaks can be related to certain recent changes in cultural practice, especially the introduction of overhead irrigation. Results are presented for control trials by trapping or by chlorophacinone baiting.     

柑橘大实蝇成虫最佳诱捕时间和诱捕地点

为有效诱捕柑橘大实蝇Bactrocera minax成虫,首先调查5个不同橘园中柑橘大实蝇成虫发生量和落果数量,计算落果率,对诱捕时间和诱捕成虫百分比进行Logistic方程拟合分析,然后调查全田、橘园、交界带、杂树林、橘园中心5个生境下柑橘大实蝇觅食高峰期成虫发生量,并对各生境下柑橘大实蝇成虫发生量和各橘园中落果率进行相关性分析及回归分析。结果表明,觅食高峰期柑橘大实蝇的最佳诱捕时间为5月31日—6月27日。除杂树林外,觅食高峰期全田、橘园、交界带和橘园中心柑橘大实蝇成虫发生量和落果率之间均呈显著正相关。通过比较5个生境拟合回归方程的判定系数和均方根误差确定在交界带生境中柑橘大实蝇成虫发生量与落果率的二次三项式模型拟合效果最好,因此,交界带为柑橘大实蝇成虫的最佳诱捕地点。     

Residual sprays for the control of the crazy ant Anoplolepis longipes (Jerd.) in the seychelles

Attempts to find suitable quick-acting toxic sprays, for the control of Anoplolepis longipes (Jerd.) in buildings, involved investigations of the toxicity and weathering properties of several insecticide formulations. Their mammalian toxicity was also considered and, particularly for indoor applications, their odour and non-staining properties. Bendiocarb, gamma-HCH and chlorpyrifos were particularly effective, killing ants rapidly after minimal contact with spray deposits, but gamma-HCH and chlorpyrifos weathered better than bendiocarb and were therefore more suitable for outdoor applications.     

Efficacy of Jordanian Isolates of Bacillus thuringiensis against the citrus leafminer,Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae)

Several laboratory experiments were conducted to test the efficacy of reference and local isolates of Bacillus thuringiensis ( Bt ) against the Middle East strain of citrus leafminer (CLM), Phyllocnistis citrella, on lemon leaves when they were applied to the surface of intact leafminer. Among the six reference strains examined, the strain Bt kurstaki H3a, 3b, 3c ( Bt 4) showed the highest toxicity after 3 days of application. Bt kurstaki also caused additive mortality to the second and third instar larvae of citrus leafminer when the bacteria were combined with Sunspray ® oil. This combination caused significantly higher mortality (63.3%) than did Bt kurstaki alone or Bt kurstaki mixed with the surfactant Surfix ® . Local Bt isolates J6 ( Bt kurstaki ) and J23 ( Bt thuringiensis, H1) showed no significant toxicity differences towards CLM when compared with the reference strain Bt 4. Addition of Bt kurstaki preparation with Vapcocidin ® (pyrethroid insecticide) reduced the required lethal concentration of the pyrethroid pesticide by up to 50%. These results emphasize the value of Bt as part of integrated programmes for controlling citrus leafminer.     

Influence of caffeine on the survival of leaf-cutting ants Atta sexdens rubropilosa and in vitro growth of their mutualistic fungus

BACKGROUND: Leaf‐cutting ants collect plant fresh material for the cultivation of their mutualistic fungus. Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae) cause great economic losses through their foraging activity, mainly in agriculture. The main control method is the application of granulated toxic baits incorporated with an active ingredient (AI). The present goal is to evaluate the effect of caffeine on in vitro growth of the mutualistic fungus and on the survival of the leaf‐cutting ants, aiming to verify the potential toxicity of this secondary metabolite over these organisms. RESULTS: Three distinct patterns of fungal growth correlated with caffeine concentration were observed: (1) no effect (0.01% caffeine); (2) intermediate growth reduction (0.05% caffeine); (3) drastic growth reduction (0.10 and 0.50% caffeine). The highest caffeine concentration causes fungus death in the first week. As for insect survival, caffeine does not seem to exert any effect. The treatments with diet containing caffeine showed similar values of M50, irrespective of caffeine concentration. CONCLUSION: As caffeine was shown to reduce growth of the mutualistic fungus of Atta sexdens rubropilosa, but with no conclusive effect on insect survival, a hypothetical explanation for the selection of different Coffea species by this leaf‐cutting ant species might be associated with caffeine toxicity to the fungus. Copyright © 2011 Society of Chemical Industry     

Maize planting time and arthropod abundance in southern Mindanao,Philippines. II. Population dynamics of natural enemies

Abstract

Beneficial arthropods were monitored in monthly plantings over 4 years in a rainfed, triple-maize cropping system in southern Mindanao, Philippines. Generalist predators and two egg parasitoids of the Asian corn borer Ostrinia furnacalis (Guenée) (ACB) did not show significant differences in abundance with respect to calendar month of planting over 39 crops. Two species of Trichogramma (T. evanescens Westwood and T. chilonis Ishii) collectively parasitized 67% of ACB egg masses and 58% eggs over the study becoming more abundant as the crop aged. The closeness of the two parasitism rates suggests that to increase parasitoid efficacy, particularly early in the crop, the best strategy would be augmentation and to increase longevity of wasps by providing carbohydrate sources to extend their searching time. Unparasitized egg masses tended to be smaller showing they were more likely to be overlooked. The ratio between the two parasitoids was 56:44 in favour of the former. Trichogramma evanescens had been introduced 2 years earlier by a government project, whereas T. chilonis probably was introduced by sugarcane estates. Prior to their introduction there were no ACB egg parasitoids in the Philippines and both are firmly established as annual parasitism levels did not continue to rise during the study. Parasitoid activity caused significant reductions in neonate ACB larval numbers beginning 7 weeks after crop emergence in an average crop. Egg parasitism rates were positively and linearly correlated with ACB egg mass density. A quadratic regression model was established between mean egg parasitism rates and egg masses size with peak parasitism rates occurring at 25 eggs per mass. Collectively 32 species of generalist predators averaged 0.9 – 1.5 individuals per plant based on weekly samplings. If ants were excluded, the average dropped to 0.1 – 0.3 per plant. Ants, dominated by Solenopsis geminata (F.), fed on ACB eggs and larvae. Coccinellids as the next most numerous were represented by three species where Micraspis crocea (Mulsant) in particular tracked ACB egg masses and probably the corn leaf aphid Rhopalosiphum maidis (Fitch) as well. Four species of orthropterans also tracked ACB egg masses. The third most abundant guild was 17 spiders with the oxyopid Oxyopes javanus Thorell and the araneid Araneus inustus (C.L. Koch) highly correlated with ACB egg mass densities. Other spiders targeted ACB moths and Atherigona oryzae Malloch adults. The predatory mirid Cyrtorhinus lividipennis Reuter probably targeted the corn leafhopper Cicadulina bimaculata (Evans) and possibly thrips Thrips palmi Karny and Megalurothrips usitatus (Bagnall). The lacewing Chrysopa sp. was abundant late in the crop when aphids were present on tassels.     

Phytophthora foot rot control in citrus with Myrothecium roridum1

Foot rot is the most important disease in citrus in Spain. Phytophthora nicotianae var. parasitica is the major cause of this disease. Field treatments with classic contact fungicides have been extensively used for many years to combat stem and trunk Phytophthora diseases in citrus, while, more recently, foliar application of the systemic fungicide fosetyl-A1 has been used with great success. It is now also possible to use a biological control method for foot rot disease. Myrothecium roridum, a cosmopolitan soil hyphomycete with high cellulolytic activity, produces toxins which are very active against Phytophthora fungi. Culture filtrates of M. roridum cultured in liquid medium with low sugar content strongly inhibit in vitro development of P.n. parasitica, P. syringae and P. capsici. In glasshouse trials employingcross inoculations of M. roridum and P.n. parasitica in stems of sweet orange and willowleaf mandarin seedlings, the bark lesions produced by Phytophthora were clearly stopped at 7 or 10 days after inoculation and the cankers subsequently did not show evident activity. In field trials, M. roridum inoculated into the roots of several citrus species limited development of cankers due to P.n. parasitica (artificial or natural infection). The good results open a new way for control of Phytophthora diseases in citrus.     

Rate, placement and timing of aldicarb applications to control Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), in oranges

BACKGROUND: The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a cosmopolitan insect pest of citrus and vectors the bacterium Candidatus Liberibacter asiaticus, a suspected causal organism of citrus greening or ‘huanglongbing’ disease. Aldicarb 150 g kg^?1 GR (Temik^® 15 G) was evaluated at three rates, two placements and three timings for ACP control in orange trees. RESULTS: Application of aldicarb at 5.6, 2.8 and 1.4 kg AI ha^?1 in March 2006 reduced adults by 58–66%, 45–46% and 25–37% respectively compared with untreated controls in two separate trials. No difference was observed in placement (one versus two sides of the tree) or tree size (8 years old versus 12 years old). Application at 5.6 kg ha^?1 in January 2007 reduced adults by 86% and shoot infestation by 77% in spring, and was generally better than the November and especially February applications. Even more striking results were evident on adults caged on treated plants for 25 days in March. Spiders and ladybeetles were equally abundant in treated and untreated trees. CONCLUSION: Aldicarb application at 5.6 kg ha^?1 to the bed side of mature citrus trees 2–3 months before spring growth can suppress ACP through spring without a direct effect on principal psyllid natural enemies. Copyright © 2008 Society of Chemical Industry