Compatibility of spinosad with predaceous mites (Acari) used to control Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)

BACKGROUND: Spinosad is a biopesticide widely used for control of Frankliniella occidentalis (Pergande). It is reported to be non‐toxic to several predatory mite species used for the biological control of thrips. Predatory mites Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) and Hypoaspis miles (Berlese) have been used for control of F. occidentalis. This study investigated the impact of direct and residual toxicity of spinosad on F. occidentalis and predatory mites. The repellency of spinosad residues to these predatory mites was also investigated. RESULTS: Direct contact to spinosad effectively reduced the number of F. occidentalis adults and larvae, causing > 96% mortality. Spinosad residues aged 2–96 h were also toxic to F. occidentalis. Direct exposure to spinosad resulted in > 90% mortality of all three mite species. Thresholds for the residual toxicity (contact) of spinosad (LT₂₅) were estimated as 4.2, 3.2 and 5.8 days for T. montdorensis, N. cucumeris and H. miles respectively. When mites were simultaneously exposed to spinosad residues and fed spinosad‐intoxicated thrips larvae, toxicity increased. Residual thresholds were re‐estimated as 5.4, 3.9 and 6.1 days for T. montdorensis, N. cucumeris and H. miles respectively. Residues aged 2–48 h repelled T. montdorensis and H. miles, and residues aged 2–24 h repelled N. cucumeris. CONCLUSION: Predatory mites can be safely released 6 days after spinosad is applied for the management of F. occidentalis. Copyright © 2011 Society of Chemical Industry     

Occurrence and host plants of Frankliniella occidentalis and Liriomyza huidobrensis in Belgium1

Increasing international trade in plants has resulted in repeated import of foreign pests into Belgium; Opogona sacchari and Coccotrypes dactyliperda are well known examples. Recently two new pests have been introduced into Belgium, Frankliniella occidentalis and Liriomyza huidobrensis. The thrips F. occidentalis appeared in the summer of 1987, and was first found in chrysanthemums. At present, this insect can be observed in floriculture, as well as in vegetable growing, where it occurs on a wide range of host plants. F. occidentalis is now considered definitely established in glasshouses in Belgium. At the end of 1989, the leafminer L. huidobrensis was found for the first time in Belgium. The damage was observed on chrysanthemums and lettuce. In 1990, this leafminer also attacked other crops, especially tomatoes and celery. Its distribution is still limited, as is the damage it causes.     

Verbena as a trap crop to suppress thrips-transmitted Tomato spotted wilt virus in chrysanthemums

The effect of verbena as a trap crop on the occurrence of western flower thrips, Frankliniella occidentalis, and the incidence of Tomato spotted wilt virus (TSWV) in chrysanthemums were investigated. Verbena cvs. Pink Parfait and/or Fancy Parfait were cultivated alongside chrysanthemum cv. Jimba in a greenhouse in the proportion of 17%–25% of the chrysanthemum plants. Verbena plants attracted vector thrips, reducing western flower thrips colonization of chrysanthemum until flower bud initiation, and markedly suppressing TSWV incidence on chrysanthemums until flowering. Significant quantities of linalool oxide pyran were produced by the flower of cv. Fancy Parfait; and the ratio of cis-linalool oxide pyran, an attractant for vector thrips, to the trans-type was approximately 1 : 5. Our results suggest that cultivation of verbena as a trap crop may be useful in integrated pest management programs as a control for thrips-transmitted TSWV in chrysanthemums.     

Integrated thrips control on glasshouse cucumbers1

Thrips are among the most dangerous pests of glasshouse cucumbers in Poland. The most frequent species, causing the greatest damage, are Frankliniella occidentalis and Thrips tabaci. The integrated programme of glasshouse cucumber protection against thrips consists of prophylactic treaments, use of the predators Amblyseius barkeri and Neoseiulus cucumeris, and agrotechnical measures.     

Developments in the integrated control of Frankliniella occidentalis in capsicum and cucumber1

Since the appearance of the western flower thrips, Frankliniella occidentalis, in European glasshouses, many attempts have been made to improve the biological methods for thrips control, originally based on the control of Thrips tabaci. Introductions of Neoseiulus (Amblyseius) cucumeris have been increased with respect to both numbers per introduction and number of releases. So-called slow-release systems have been developed to ensure better establishment of the predator on the plant. New control agents have been tested: the predatory bug Orius insidiosus and the entomopathogenic fungus Verticillium lecanii. Additional control methods are: 1) the use of polybutenes as an insect glue on yellow polythene covers of the rock-wool mat; 2) newly developed blue sticky traps. These new developments and prospects are discussed.     

M?glichkeiten der Bek?mpfung des Kalifornischen Bl��tenthripses Frankliniella occidentalis (Pergande) mit nachgewiesener Insektizidresistenz in Schnittrosen unter Glas

Due to resistance to insecticides (or plant protecting agents) the western flower thrips Frankliniella occidentalis is difficult to combat in cut roses cultures with conventional methods. In that case the predatory mite Amblyseius cucumeris could be a very effective biological alternative when applied in high numbers of 1000 mites per square meter against low density thrips population. The key to success is early application at the beginning of the vegetative growth before the thirps becomes active and the first larvae appear. The efficiency of the mites is not sufficient when the thirps population density in spring is high. Caused by the fecundity and fast development of Frankliniella occidentalis in higher temperatures, the application of chemical protecting agents in summer could be unavoidable. Because of the proven resistance Western flower thrips developed against the insecticides permitted in Germany, the chemical agents may not be effective. Only an optimal application can provide a satisfactory reduction of the thrips population. The development stage of the roses must be taken into account as well as right application intervals of insecticides. In order to develop a sufficient and effective control of Western flower thrips Frankliniella occidentalis and improve resistance management the application of predatory mites seems to be inevitable in future.     

Ribotyping of EntomopathogenicVerticittium lecanii in Japan

To estimate the genetic diversity in 30 isolates ofVerticillium lecanii from aphids, whiteflies, mite and black pine in Japan, including two commercialized strains (Mycotal and Vertalec), DNA polymorphisms in ribosomal DNA of those isolates were analyzed using polymerase chain reaction (PCR). The internal transcribed spacer (ITS) and intergenic spacer (IGS) regions of the nuclear ribosomal RNA gene of each isolate were analyzed by PCR-RFLP (restriction fragment length polymorphism). The size of the PCR product from the ITS region was ~ 580 bp in 27 of the isolates. A 600 bp ITS product was detected in Mycotal and Vertalec. One Japanese isolate produced both the 580 bp and 600 bp products. Enzymatic digestion of the ITS region with Sau3A I,Msp I,Hae III andRsa I revealed RFLPs that consisted of eight haplotypes. Mycotal and Vertalec were specific haplotypes that differed from other isolates. The Japanese isolates had a complex relationship with the original host, but we identified several specific haplotypes common to an aphid origin. Ten distinct IGS haplotypes were detected in the IGS region, some of which were associated with aphid and whitefly origins. These results suggest that the haplotype of rDNA RFLP analysis can be used for studying genetic diversity inV. lecanii.     

Elevated humidities for control of chrysanthemum pests with Verticillium lecanii

Integrated pest control on chrysanthemum is now a possibility. Verticillium lecanii (Zimm.) Viegas is one of the key components as, under the right conditions, it will provide good control of pests such as aphids, thrips and whitefly. High humidity for a number of nights per week is critical for reliable pest control with this fungal pathogen. These conditions can be easily and safely obtained by fogging water over the crop at night. Four consecutive nights of high humidity per week or a cycle of two nights of high humidity and two nights ambient have given excellent pest control with no adverse effect to the crop.     

不同花色菊花品种上西花蓟马种群密度及雌雄性比

为明确不同花色菊花品种上西花蓟马Frankliniella occidentalis发生情况及种群变化规律,利用蓝色粘虫板调查了大棚种植的7种单色(黄色、橙色、白色、绿色、粉色、紫色、红色)以及4种双色(黄绿、黄红、白绿、黄白)菊花品种上不同时期西花蓟马的种群密度及雌雄性比。结果表明,根据四分位法得到西花蓟马的发生早期与菊花苗期重合,主要发生期与菊花开花期重合,发生晚期为切花后生长期。在所有单色菊花品种中,西花蓟马在黄色菊花品种上的种群密度最高,主要发生期虫口密度达19.98头/板;且雌雄性比最大,为5.85,显著高于其它单色菊花品种上的雌雄性比。在所有双色菊花品种中,黄绿菊花品种上的西花蓟马种群密度最高,主要发生期虫口密度达26.89头/板,显著高于其它双色菊花品种上数量,且雌雄性比也最大,为6.87。菊花开花是导致西花蓟马种群迅速上升和种群中雌虫比例迅速增加的主要原因,且西花蓟马偏好为害与黄色花色相关的菊花品种。     

Biological control in protected strawberry in northern Italy1

Biological control is currently being used in 100 ha of tunnel-grown strawberry in northern Italy. Second-instar larvae of Chrysoperla carnea are released (18 larvae per m²) against aphids when more than 30% of leaflets are infested. Releases of Phytoseiulus persimilis (4–6 predatory mites per m²) are also being used in IPM strategies against Tetranychus urticae; wild P. persimilis populations also occur in the test area, which is near the Adriatic coast. Releases of predators are also successful in the field.     

Biological control in the Maltese Islands — past initiatives and future programmes1

Past records of introduced predators and parasites for biological control programmes in the Maltese Islands are reviewed. Literature on this subject is very limited, difficult to obtain and to confirm. During the last 10 years, several exotic pest species were accidentally introduced into the Maltese Islands, including Aleurothrixus floccosus, Bemisia tabaci, Liriomyza spp., Frankliniella occidentalis and Phyllocnistis citrella. Natural enemies have been imported to control these pests. These include Dacnusa sibirica and Diglyphus isaea for the control of leafminers; Encarsia formosa, Eretmocerus californicus and Macrolophus caliginosus for regulation of Bemisia tabaci; Cales noacki against Aleurothrixus floccosus; Orius laevigatus, O. insidiosus and Neoseiulus cucumeris against thrips; Aphidius colemani and Aphidoletes aphidimyza for the control of glasshouse aphids and Phytoseiulus persimilis and Amblyseius californicus for the control of the red spider mite. Encarsia lutea and Eretmocerus mundus have been recorded from Bemisia tabaci in Malta. Faunistic studies of parasitic Hymenoptera occurring in Malta are currently being carried out. The data is presented and the significance of utilizing local natural enemies is briefly discussed.     

Biological control of the Western flower thripsFrankliniella occidentalis in cucumber using the entomopathogenic fungusMetarhizium anisopliae

Biological control of the western flower thrips (WFT)Frankliniella occidentalis, using the entomopathogenicMetarhizium anisopliae-7 (M. a-7) strain was studied in three consecutive seasons under greenhouse conditions. Cucumber plants infested with WFT were sprayed with spore suspension of the fungusM. a-7 (0.5 g m^-2), or the soil was treated with dry powder of the fungus (0.5 g m^-2); the control was without fungus application. In the 1997 spring experiment, when the cucumber plants were initially infested with only three or four insects per leaf, the spore suspension spray caused a significant reduction in growth of the thrips population compared with the other treatments and the control. However, in the 1997 summer experiment, when the plants were initially heavily infested with WFT (10–15 insects per leaf), the spray treatment caused only a modest reduction in WFT population growth, and only after 4 weeks of treatment was the reduction significant. In the 1999 experiment, with a low initial WFT population of three or four insects per leaf, the spray treatment was effective in reducing the population growth to a lower level than in the other treatments or control. TheM. a-7 strain was found to be effective in reducing the population growth of WFT under greenhouse conditions, particularly when the initial thrips population was low to moderate. http://www.phytoparasitica.org posting Nov. 4, 2001.     

Comparative analyses of the toxic effects of imidacloprid and spirotetramat on Frankliniella occidentalis (Pergande), the vector of tomato zonate spot virus: a laboratory assay

The tomato zonate spot virus (TZSV) is responsible for substantial yield losses in vegetables, tobacco and other cash crops in China in recent years. The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera, Thripidae), is the main vector of TZSV in Yunnan Province. Because controlling the population of insect vectors is the most efficient way to prevent epidemics of viral diseases, we conducted laboratory assays to assess the potential of using spirotetramat as an alternative to imidacloprid in controlling F. occidentalis. Our results demonstrated that spirotetramat was significantly more lethal than imidacloprid to F. occidentalis at different concentrations. The LC₃₀, LC₅₀ and LC₉₀ values of spirotetramat were all much lower than those of imidacloprid after the same time of treatment. Frankliniella occidentalis was more sensitive when treated with spirotetramat than imidacloprid at the concentrations of 500, 250, 125 and 62.5mg/L, and the median lethal concentrations (LC₅₀) were 285.53, 82.24 and 11.19mg/L at 12, 36 and 72 hours after treatment, respectively. Spirotetramat caused 100% mortality of F. occidentalis at 500 and 250 mg/L after 48 hours treatment, and at the lowest concentration 125 mg/L at 72 hours after treatment, respectively. Field experiments carried out elsewhere have confirmed our findings. Together they allow us to conclude that spirotetramat is a promising pesticide for the control F. occidentalis in China.     

Insect-trapping Hairs on Potato Plants

Abstract

The ability of glandular hairs on the foliage of the wild potato species Solanum polyadenium and S. berthaultii to trap mite and insect pests is illustrated by scanning electron micrographs. Both potato species have hairs with four-lobed heads which release a sticky substance when ruptured. On S. polyadenium these hairs trapped aphids, Colorado beetle larvae and a leafhopper Javasella pellucida. S. berthaultii also has hairs with a sticky droplet at their tips; these hairs trapped such small pests as spider mites, thrips and larval mealybugs. Adult whitefly were not trapped because a powdery wax from the whiteflies coated the hairs. It is suggested that these glandular hairs could help protect potato crops by trapping many foliage pests, including disease vectors.     

Biological control of pests in Swedish pot plant production1

Biological control of glasshouse pests is nowadays an important factor in the production of pot plants in Sweden. During 1990, more than 100 growers applied one or more methods of biocontrol, some only in propagation units but many during the entire production of several crops. Poinsettia is the major crop in this context. Eighty growers were interviewed about their experiences of various biocontrol methods. The use of Neoaplectana carpocapsae against sciarids and Otiorhynchus sulcurus was the most popular and reliable method. Next comes Encarsia formosa against whiteflies. Other methods include Verticillium lecanii against whiteflies and thrips, Aphidius matricariae against aphids, and predatory mites against thrips and spider mites.     

Note: First record in crete ofHercinothrips femoralis in greenhouse banana plantations

In 2004 the banded greenhouse thrips,Hercinothrips femoralis (Reuter) (Thysanoptera: Thripidae), was recorded for the first time in greenhouse-grown organic banana in the area of Sitia (northeastern Crete). Banana fruits were severely damaged by the thrips infestation and a typical smoky-red discoloration of the fruit was observed. Pest control was poor using either high-pressure washing with potassium fatty acids, or commercially available thrips predatorsNeoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae) andOrius laevigatus (Fieber) (Hemiptera: Anthocoridae). During 2005H. femoralis was also found causing severe damage in conventional banana plantations in Arvi, the main banana-growing area of Crete. http://www.phytoparasitica.org posting Sept. 17, 2006.     

Insecticide Resistance in the Western Flower Thrips, Frankliniella occidentalis

The western flower thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) is a serious pest on a wide range of crops throughout the world. F. occidentalis is difficult to control with insecticides because of its thigmokinetic behaviour and resistance to insecticides. Pesticide resistance can have a negative impact on integrated pest management programmes with chemical control as one of the components. Resistance to a number of different insecticides has been shown in many populations of F. occidentalis. This flower thrips has the potential of fast development of resistance owing to the short generation time, high fecundity, and a haplodiploid breeding system. The mechanisms conferring insecticide resistance in insects can be divided into four levels. First, an altered behaviour can aid the insect to avoid coming into contact with the insecticide. Second, a delayed penetration through the integument will reduce the effect of the insecticide at the target site. Third, inside the insect, detoxification enzymes may metabolise and thereby inactivate the insecticide. Fourth, the last level of resistance mechanisms is alterations at the target site for the insecticide. Knowledge of resistance mechanisms can give information and tools to be used in management of the resistance problem. Recently, studies have been carried out to investigate the underlying mechanisms conferring resistance in F. occidentalis. It appears that resistance in F. occidentalis is polyfactorial; different mechanisms can confer resistance in different populations and different mechanisms may coexist in the same population. Possible resistance mechanisms in F. occidentalis include: reduced penetration, detoxification by P450-monooxygenases, esterases and glutathione S-transferases, and alterations of acetylcholinesterase, the target site for organophosphate and carbamate insecticides. Target site resistance to pyrethroids (knockdown resistance) may also be a resistance mechanism in F. occidentalis.     

Elucidating resistance in cotton genotypes to whitefly, <Emphasis Type="Italic">Bemisia tabaci,</Emphasis> by population buildup studies

Plant resistance has become an important component of integrated pest management (IPM) for management of whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), an important pest of cotton in India. The present studies were undertaken to standardize the plant stage and identify resistant cotton genotypes against whitefly. Nine plant stages of F846, a susceptible cotton genotype, were exposed to whitefly for 25 days under no-choice conditions. The population buildup (eggs, nymphs, pupae and adults) was recorded. The 12-, 14- and 16-leaf stages were suitable for plant resistance studies against whitefly, and the 14-leaf stage was taken for further studies. Ten cotton genotypes of Gossypium hirsutum and two of G. arboreum were covered with split cages in which five pairs of B. tabaci (F₁) were released. The population buildup was recorded to categorize genotypes as resistant, moderately resistant, moderately susceptible or susceptible. The experiment was repeated with F₂ and F₃ generation whiteflies. Based on overall average score of three experiments, LD694 was rated as resistant; LK861, Supriya, RS2013, CNH911 and PA183 as moderately resistant; IS-376/4/1/20/72, NHH44, TxMaroon2-78, Bt 6304 and RS2098 as moderately susceptible; and F846 as susceptible. LD694 was found to be resistant in three consecutive generations of whitefly.     

Mechanisms conferring resistance of Western flower thrips to bendiocarb

Mechanisms associated with bendiocarb resistance were examined in two strains of western flower thrips, Frankliniella occidentalis (Pergande), that differed in their susceptibility to this carbamate by 13.6-fold. No appreciable differences between the two strains in [¹⁴C] bendiocarb penetration and excretion were detected; however, bendiocarb was metabolised substantially faster by the resistant KCM thrips than by the more susceptible UMC thrips. No appreciable difference between the two strains was found in the sensitivity of acetylcholinesterase activity to inhibition by bendiocarb. It was concluded that bendiocarb resistance in KCM western flower thrips was due to enhanced metabolism that probably was mainly oxidative in nature.     

Effects of planting date and environmental factors on fusarium ear rot symptoms and fumonisin B1 accumulation in maize grown in six North American locations

Fusarium ear rot, primarily caused by Fusarium verticillioides, causes losses in grain yield and quality and can result in contamination of grain by mycotoxins, primarily fumonisin B₁. Disease severity and fumonisin B₁ contamination vary considerably among maize‐growing regions and from year to year. A 2 year field study was conducted in six locations in the USA, to evaluate the roles of planting date, maize hybrid, rainfall, temperature and insect pests in the variation in fusarium ear rot symptoms and fumonisin B₁ contamination. Grain samples were inspected to determine percentage of kernels with fusarium ear rot symptoms, categorized as ‘moulded’ or ‘starburst’; grain was also analysed by ELISA for fumonisin B₁. Hybrid and planting date frequently had significant effects (P ≤ 0·05) on fusarium ear rot and fumonisin B₁ contamination. Earlier planting consistently resulted in lower ear rot severity, fumonisin B₁ levels and insect damage. Mould symptoms were highly correlated with thrips populations (Frankliniella occidentalis) (r = 0·78) and with fumonisin B₁ concentration (r = 0·89). The starburst symptom was not as closely correlated with thrips (r = 0·33) or fumonisin B₁ (r = 0·18). A multiple linear regression model identified highly significant effects on fumonisin B₁ for thrips, lower average daily precipitation after flowering, and location. These results strengthen the evidence that locations with high populations of ear‐infesting thrips and dry conditions after pollination have an increased risk of fumonisin contamination, and suggest that high fumonisin levels are much more likely in visibly moulded kernels compared to those with ‘starburst’ symptoms.