Effectiveness of Trichogramma pretiosum in controlling lepidopterous pests of soybean crops

In order to reduce the use of insecticide, the application of Beauveria bassiana may be an alternative control. The objective of this study was to evaluate the efficacy of B. bassiana for controlling mungbean pest. The experiment was conducted in Ngale Research Station from February to May 2017, using randomized block design, seven treatments, four replicates. The treatments were frequency of application; P1= six times, P2= five times, P3= four times, P4= three times, P5= once, P6= full protection using chemical insecticide, and P7= no protection. Application of B. bassiana four to six times can suppress the population of Empoasca sp., Riptortus linearis, and Maruca testulalis, but did not significantly different with the application of chemical insecticide. Based on the seed weight, application of B. bassiana six times (659.7 g/plot) led to significantly high as compare with the application of chemical insecticide (374 g/plot). Application of B. bassiana tended to be secure to natural enemies, especially Coccinella sp., Oxyopes javanus, and Paederus fuscipes. Both of those predators were not found on the application of chemical insecticide. Hence, B. bassiana can be recommended as a biological agent in integrated pest management component on mungbean because of effective and environmentally friendly.

The soybean aphid, Aphis glycines Matsumura, has become established as a serious pest of soybean, Glycine max (L.) Merr., since it was first found in North America in 2000 and has caused millions of dollars in economic losses. While the application of chemical insecticides is the only means to control the soybean aphid at present, genetic resistance to the aphid was recently discovered in soybean. A single dominant gene named Rag1 that controls resistance to the soybean aphid was found in the cultivar Dowling. Another cultivar found to have strong antibiosis‐type resistance to the soybean aphid was Jackson. The primary objective of this study was to determine the inheritance of resistance to the soybean aphid in Jackson. Segregation of resistance was analyzed in F2 and among F2–derived F3 (F2:3) families produced from crosses between Jackson and the susceptible soybean cultivar Loda. Segregation of F2 plants was 247 resistant to 97 susceptible and fit a 3:1 genetic ratio (P = 0.17). Segregation among F2:3 families was not clear because a number of susceptible F2 plants did not produce a sufficient amount of seed for progeny testing. Ignoring the susceptible class, the segregation of F2:3 families fit a 1:2 (all resistant/segregating) ratio. These results indicated that a single dominant gene controlled resistance in Jackson. There is no known genetic relationship between Jackson and Dowling. The genetic relationship between Rag1 in Dowling and the gene in Jackson is unknown.

The project was developed at the IAC, in Votuporanga, São Paulo State, Brazil. The experimental design used was randomized blocks with four repetitions, using five treatments: sorghum culture: standard treatment (without insecticide application, T1); Colossus BT-2 (B. thugingiensis subsp. Kurstaki) and Comander (C. subtlesugae) at doses of 0.3 L ha-1 and 0.2 L ha-1, respectively (T2); 0.4 L ha-1 and 0.3 L ha-1, respectively (T3); 0.5 L ha-1 and 0.4 L ha-1, respectively (T4); application of chemical insecticides (T5); bean culture: standard treatment (without insecticide application, T1); Application of Ultron-S+A (S. spinosa) at doses of 0.2 L ha-1 (T2); 0.3 L ha-1 (T3); 0.4 L ha-1 (T4); application of chemical insecticides (T5). The plots were 5.0 x 5.0 m, totaling 25 m2. In sorghum culture was evaluated the incidence (%) of plants with the presence of caterpillars in the leaves; the incidence (%) of plants with caterpillars attack symptoms in the leaves; the incidence (%) of plants with the presence of aphids in the leaves; the incidence (%) of plants with symptoms of attack of aphids in the leaves; final stand ha-1 and grain yield ha-1. In bean culture was evaluated the incidence (%) of plants with the presence of caterpillars in the leaves; the incidence (%) of plants with symptoms of attack of caterpillars in the leaves; the incidence (%) of plants with the presence of thrips in the leaves; the incidence (%) of plants with thrips attack symptoms in the leaves; final stand ha-1 and grain yield ha-1.

A review of research on Sunn Pest {Eurygaster integriceps Puton (Hemiptera: Scutelleridae)} management published 2004–2016

The effect of chemical insecticides on the structure and diversity of arthropod communities in various vegetable fields and the restoration of their biodiversity after stopping application of chemical insecticides were studied. The results showed that the effect of chemical insecticides on the arthropods in vegetable fields could be characterized the species structure, the diversity index and the evenness of species distribution. Components of arthpod species depended closely on the species number of insect pests, predatory natural enemies and spiders. Investigations showed that the numbers of species in the vegetable fields managed with chemical insecticides were obviously reduced, and their diversity indices were lower comparing with that without chemical insecticides. When the applications of chemical insecticides were stopped in vegetable fields, the index of population trend (I) of dominant insect pests decreased greatly, the control effect of natural enemies on major insect pests increased, and the diversity index of arthropod increased at the same time. Thus, limiting the application of chemical insecticides, resuming the environment of vegetable fields destroyed by using chemical insecticides, escalating the control ability of natural enemies on main insect pests will play an important role in the ecological control of insect pests in vegetable fields.

Abstract: The effect of any management strategy on pest population levels must be researched and determinations need to be made as to how that strategy might work based on the control objectives. In certain areas of Europe, the objective is to contain or eradicate the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, population. In order to evaluate the impact of insecticide seed coatings and/or planting‐time applications of insecticides as WCR population suppressors, plot trials and large field observations were carried out in Italy over a 5‐year period. Larval, pupal and adult densities, along with root damage ratings, were estimated at different locations. Data from these studies revealed that the number of WCR adults emerging from untreated plots did not differ from the number of beetles emerging from those treated with insecticides, whether as seed coating or in‐furrow applications. Both seed insecticide coatings (imidacloprid, fipronil, thiamethoxam, tefluthrin) and soil insecticides applied in‐furrow (chlorpyrifos, diazinon, tefluthrin) did not reduce the number of beetles emerging from monoculture fields, either in plot trials or large field observations. Observations in the USA had previously shown that soil insecticides applied at planting time partially protected basal roots from economic damage, but did not reduce corn rootworm populations. Similarly, in Europe, it has been demonstrated that not only the application of soil insecticides at planting time but also insecticide seed coatings have no role in the containment and/or eradication of WCR. Although insecticide seed coatings and soil insecticides applied in‐furrow may provide protection against economic damage to roots, these management strategies do not have an impact on WCR populations and therefore are useless in WCR containment and eradication programmes.

The Jassid, Amarasca bigutulla bigutullaa is an important sucking pest of the okra crop. An experimental study was conducted during 2018 to check the comparative toxicity of nitenpyrem and neem oil against jassid under okra field conditions. The study revealed that 24 hours after treatment, nitenpyrem was found more toxic and effective with maximum reduction of jassid population (72.15%). Whereas, 120 hours after treatment with 4% neem oil, 15.05% jassid reduction was observed. The mortality rate of the jassid was increased with increasing in time after application of chemical insecticides. The study concluded that insecticide was most toxic and gives higher mortality of jassid as compared to neem oil. Keywords: Abelmoschus esculentus, Malvaceae, Amarasca bigutulla bigutullaa, botanicals, insecticides, Pakistan

The greenhouse whitefly, Trialeurodesvaporariorum Westwood, is an important pest of field and greenhouse crops of horticultural and ornamental plants. In integrated pest management programs its control is mainly based on the release of biological control agents and application of chemical insecticides. Neonicotinoids are relatively new chemicals currently applied for the chemical control of T. vaporariorum. However, cases of development of insecticide resistance to neonicotinoids have already been reported. The state of resistance to neonicotinoid insecticides for populations of the greenhouse whitefly in Greece is currently unknown. The objective of our study was to screen a number of whitefly populations for resistance to the neonicotinoids imidacloprid and thiacloprid. Seven whitefly populations were collected from tomato greenhouse crops from different areas of central and northern Greece. LC50 values were estimated for all populations following the method proposed by the Insecticide Resistance Action Committee (IRAC). The development of resistance to both neonicotinoids was confirmed for all tested populations with resistance ratios ranging from 1.5 to 4.4-fold and from 1.4 to 12.2-fold for imidacloprid and thiacloprid, respectively. We discuss our results with regard to the development of neonicotinoid resistance in T. vaporariorum populations and its implications for whitefly control.

Ecotoxicological effect of fenitrothion on Trissolcus nigripedius (Hymenoptera: Scelionidae) an egg parasitoid of Dolycoris baccarum (Hemiptera: Pentatomidae)

Stink bugs (Hemiptera: Pentatomidae) are important economic pests of many agricultural crops, and have become one of the most difficult pest complexes to control in field crops, vegeta bles and fruit trees (McPherson & McPherson 2000). Stink bugs usually attack developing fruit ing structures, and direct damage to the fruit is caused by insertion of their stylets to feed on plant fluids. In soybeans (Glycine max (L.) Merr.), stink bug feeding can cause delayed maturity and reduce seed quality, yield and germination (Un derbill 1934; Chyen et al. 1992). The adoption of an early soybean production system has resulted in an increase in stink bug populations (Baur et al. 2000). The stink bug complex in the south contains the native spe cies Euschistus servus (Say) (brown stink bug), Nezara viridula (L.) (southern green stink bug) and Acrosternum hilare (Say) (green stink bug). (Taxonomists have proposed changing the name A. hilare to Chinavia hilaris (Say), but the En tomological Society of America has not approved this yet [David Rider, personal communication].) Historically, the southern green stink bug has had the greatest economic impact on southern USA soybean producers (Panizzi & Slansky 1985). Prior to 2000, Piezodorus guildinii (West wood) (redbanded stink bug) had never been an economic threat to soybean production in the U.S., although it has long been a serious pest in South America (Panizzi 1985). The redband ed stink bug has currently spread throughout Louisiana and is the dominant stink bug spe cies, comprising 59 to 72% of the total stink bugs found in soybean throughout the growing season (Temple et al. 2011a). Stink bug management can require multiple applications of broad-spectrum organophosphate or pyrethroid insecticides. The redbanded stink bug is very tolerant of many products available for stink bug control on soybean and, consequent ly, insecticide applications have significantly in creased (Temple et al. 2011b). Further, these in secticides applications negatively impact natural enemies, and may lead to population resurgences of other soybean pests (Panizzi & Slansky 1985). As a result, we are always watchful for possible biological control organisms that may reduce stink bug populations. During the summer of 2009, approximately 100 stink bugs were collected for bioassays from Louisiana soybean fields using 38-cm-diam sweep nets and returned to the laboratory. After about 24 h, mermithid nematodes were found to have emerged from field-collected adult, A. hilare and P. guildinii. The nematode from P. guildinii emerged on 6 Oct 2009, and had been collected from Ben Hur Research Station in Baton Rouge (30°22'14.3538N -91°9'52.236W) (Figs. 1A and IB). The nematode collected from A. hilare emerged on 30 Sep 2009 (Fig. 1C). It was collected at Macon Ridge Research Station in Winnsboro (32°8'1.6542 N -91°41'57.5484 W). An addi tional specimen was discovered in a 1992 insect collection emerging from a 4th instar nymph of A. hilare (Fig. ID) that had been preserved in 90% alcohol. This sample was collected 23 Sep 1992 from the Rice Research Station in Crowley (30°4'22.0416N -92°20'54.2112W). The rainfall for the 4 wk before emergence for all nematode infections was approximately 4.5-cm above aver age. The increased precipitation may have made the environment more conducive to the nema tode's survival.

Root consumption and damage estimates caused by Phyllophaga capillata and Aegopsis bolboceridus (Coleoptera, Melolonthidae) larvae in soybean and maize in central Brazil

Anticarsia gemmatalis (velvetbean caterpillar) and Chrysodeixis includens (soybean looper) are two important defoliation pests of soybeans. In the present study, we have investigated the susceptibility and brush border membrane-binding properties of both species to Bacillus thuringiensis Cry1Ea toxin. Bioassays performed in first-instar larvae demonstrated potent activity against both soybean pests in terms of mortality or practical mortality. Competition-binding studies carried out with 125Iodine-labelled Cry1Ea, demonstrated the presence of specific binding sites on the midgut brush border membrane vesicles (BBMV) of both insect species. Heterologous competition-binding experiments indicated that Cry1Ea does not share binding sites with Cry1Ac or Cry1Fa in either soybean pest. This study contributes to the knowledge of Cry1Ea toxicity and midgut binding sites in A. gemmatalis and C. includens and sheds light on the cross-resistance potential of Cry1Ea with other Bt proteins aimed at controlling lepidopteran pests in soybeans.

Rice production faces many challenges including damages due to pest infestation in storage after harvest. Stored rice grains are often under threat and damage from pests such as rice weevil which resulted in reduction of the quality and quantity. Application of chemical insecticides helps to control this pest, however, it gives negative impacts to the environment and human health. Application of plant-based insecticides including the use of wood vinegar can become an alternative to the conventional method. This work describes the effectiveness of wood vinegar as bioinsecticide to inhibit the rice weevil’s activity by assessing the repellency, mortality and antifeedant activity at different concentration of 50, 100, 150 and 200 rpm. Wood vinegar showed high repellency of 98.3% towards rice weevils at 200 ppm after 5 hours of exposure times. Increased in concentration affects in increased mortality with highest number of 97% recorded at 200 ppm. The lethal concentration (LC) of wood vinegar was calculated to be 77.62 ppm. Antifeedant activity resulted in reduction of weight loss in stored rice with lowest reduction of 2% at 200 ppm. This promising result reflects the ability of wood vinegar as insecticidal agents in management and control of stored-grain pest.

The Asian citrus psyllid (ACP) Diaphorina citri vectors the causative agent of citrus greening disease that has the capacity to decimate citrus production. As an alternative and more sustainable approach to manage D. citri than repeated application of chemical insecticides, we investigated the potential use of the bacteria-derived pesticidal protein, Mpp51Aa1, when delivered by transgenic Citrus sinensis cv. Valencia sweet orange or Citrus paradisi cv. Duncan grapefruit. Following confirmation of transcription and translation of mpp51aa1 by transgenic plants, no impact of Mpp51Aa1 expression was seen on D. citri host plant choice between transgenic and control Duncan grapefruit plants. A slight but significant drop in survival of adult psyllids fed on these transgenic plants was noted relative to those fed on control plants. In line with this result, damage to the gut epithelium consistent with that caused by pore-forming proteins was only observed in a minority of adult D. citri fed on the transgenic Duncan grapefruit. However, greater impacts were observed on nymphs than on adults, with a 40% drop in the survival of nymphs fed on transgenic Duncan grapefruit relative to those fed on control plants. For Valencia sweet orange, a 70% decrease in the number of eggs laid by adult D. citri on transgenic plants was noted relative to those on control plants, with a 90% drop in emergence of progeny. These impacts that contrast with those associated with other bacterial pesticidal proteins and the potential for use of Mpp51Aa1-expressing transgenic plants for suppression of D. citri populations are discussed. IMPORTANCE Pesticidal proteins derived from bacteria such as Bacillus thuringiensis are valuable tools for management of agricultural insect pests and provide a sustainable alternative to the application of chemical insecticides. However, relatively few bacterial pesticidal proteins have been used for suppression of hemipteran or sap-sucking insects such as the Asian citrus psyllid, Diaphorina citri. This insect is particularly important as the vector of the causative agent of citrus greening, or huanglongbing disease, which severely impacts global citrus production. In this study, we investigated the potential of transgenic citrus plants that produce the pesticidal protein Mpp51Aa1. While adult psyllid mortality on transgenic plants was modest, the reduced number of eggs laid by exposed adults and the decreased survival of progeny was such that psyllid populations dropped by more than 90%. These results provide valuable insight for potential deployment of Mpp51Aa1 in combination with other control agents for the management of D. citri.

Control of Curculio caryae (Coleoptera: Curculionidae) with Reduced Rates of a Microbial Biopesticide