Egg Parasitism Research Articles

Substantial genetic mixing among sexual and androgenetic lineages within the clam genus Corbicula

“Occasional” sexuality occurs when a species combines clonal reproduction and genetic mixing. This strategy is predicted to combine the advantages of both asexuality and sexuality, but its actual consequences on the genetic diversity and species longevity are poorly understood. Androgenesis, a reproductive mode in which the offspring inherits its entire nuclear genome from the father, is often reported as a strictly clonal reproductive mode. Androgenesis is the predominant reproductive mode within the hermaphroditic, invasive lineages of the mollusk genus Corbicula. Their ability to reproduce clonally through androgenesis has been determinant in their invasive success, having colonized during the 20th century American and European freshwater systems, where they became notorious invaders with a widespread, global distribution. However, in androgenetic Corbicula clams, occasional genetic mixing between distinct lineages has also been observed when the sperm of one lineage fertilizes the oocyte of another one. Because of these occasional introgressions, the genetic relationships between Corbicula species remained unclear, and the biogeographic origins of the invasive androgenetic lineages have been challenging to identify. To address these issues, we analyzed the patterns of allele sharing for several nuclear and mitochondrial molecular markers among Corbicula individuals collected across both the native and invasive range. Our results show the occurrence of an allelic pool encompassing all Corbicula freshwater species worldwide, including sexual and androgenetic ones, which highlights the substantial genetic mixing within this genus. However, the differences in allele sharing patterns between invasive lineages, and the low diversity within each lineage, suggest recent, distinct biogeographic origins of invasive Corbicula androgenetic lineages. Finally, the polyploidy, high heterozygosity, and hybrid phenotypes and genotypes found in our study probably originated from hybridization events following egg parasitism between distinct Corbicula lineages. This extensive cross-lineage mixing found in Corbicula may generate nuclear diversity in an otherwise asexually reproducing species.

Pollinator biological traits and ecological interactions mediate the impacts of mosquito-targeting malathion application

Mosquito adulticides are perceived by the public as detrimental to nontarget arthropods, contributing to declines of native and beneficial insects. However, the actual impact of adulticides on nontarget arthropods in nature needs to incorporate biological and ecological elements. Here, we investigated the effect of biological/behavioral traits (butterfly roosting at different heights, roosting in sites underneath foliage, bumblebee hive usage) and interactions (parasitism, predation) of pollinators (butterflies and bumblebees) that could mediate the impacts of malathion application in manipulative semi-field experiments in Florida, USA. Roosting height from the spray route had a significant negative relationship with mortality of butterflies treated with ULV malathion, with high survival at the highest roosting height (7 m), but butterflies roosting among vegetation did not have higher survival. Bumblebees with hive access had significantly higher survival than bumblebees without hive access. Host plants treated with ULV malathion significantly reduced parasitism of monarch eggs by Trichogramma platneri, but increased predation of monarch caterpillars by Polistes paper wasps. These data provide insight into the realistic impacts of adulticide applications on pollinators in nature which will enable mosquito control districts to better limit nontarget effects of adulticide treatments and may help to address concerns related to potential nontarget effects.

Functions of Egg-Coating Substances Secreted by Female Accessory Glands in Alderflies, Fishflies and Dobsonflies (Megaloptera).

Simple SummaryEgg masses of the insect order Megaloptera are coated with female accessory gland substances and are diverse in shape, color, and surface structure. Female alderflies (family Sialidae) and fishflies (family Corydalidae, subfamily Chauliodinae) lay eggs in a single layer on the substrate (although the eggs are occasionally multi-layered in the fishfly genus Nigronia), and the accessory gland substances are usually brown. In contrast, dobsonflies (Corydalidae, Corydalinae) lay a multi-layered hemispherical egg mass, and the accessory gland substances differ in color and chemical properties among genera and species. Egg masses of the dobsonfly genus Protohermes are coated with a sticky substance, while those of other dobsonflies are covered with hardened white powders, both of which contribute to the prevention of egg desiccation. The accessory gland substances of most species of Megaloptera also function to protect eggs from attack by oophagous predators, such as ladybird beetles and ants. The information on the parasitoids of Megaloptera egg masses are also discussed based on the present and previously reported observations.Eggs of insects are immobile and must endure harsh environmental conditions (e.g., low temperatures in winter and aridity in summer) and avoid attack by egg-eating predators, egg parasites, and microbes. Females of Megaloptera lay their eggs as a single- or multi-layered egg mass, which is coated with chemical substances secreted from the female reproductive accessory glands. In this study, we observed the egg masses laid by females of two species of Sialidae (alderflies), nine species of Chauliodinae (fishflies), and 23 species of Corydalinae (dobsonflies) belonging to the order Megaloptera and examined the functions of accessory gland substances coating the laid eggs. The female accessory gland is a single tube in alderflies and fishflies but a paired pouch in dobsonflies. The amount and color of the gland substances differ greatly among species. These substances prevent egg desiccation, inhibit egg feeding by ladybird beetles, and repel ants. Most characteristics of the egg mass structures and the effectiveness of accessory gland substances reflect the phylogeny of Megaloptera, although some differ among closely related taxa.

Brown Planthopper Egg Parasitization in Rice Fields with Different Growth Ages

The brown planthopper, Nilaparvata lugens Stål. (Hemiptera: Delphacidae), is one of the most important pests attacking rice plants. One of the strategies to control this pest is by using natural enemies, including egg parasitoids. This study aimed to investigate the species of N. lugens egg parasitoids and their parasitism levels in one rice ecosystem with different growth stages. The research was conducted by selecting three rice plots aged 3, 6, and 10 weeks after planting. Potted rice plants with N. lugens eggs were placed in those rice plots for two days and recollected for observations. The same release was repeated 3 weeks later at the same rice plots in the same site. Egg parasitoids of N. lugens found during this study were Oligosita sp. and Anagrus sp. The highest number of egg parasitoids were found at the rice plants aged 6 weeks after planting with 14.50 and 13.50 individuals collected during first and second trapping, respectively. In addition, the level of parasitism ranged from 6.89-22.26% with the highest parasitism was occurred in the 6-week old rice. These findings may suggest that different rice planting dates may benefit the egg parasitoids of N. lugens which could reduce the risk of outbreaks.

Biological control in a changing climate: plant-mediated impact of elevated CO2 concentration on Lobesia botrana eggs and egg parasitism by Trichogramma cacoeciae

Climate change can affect biological pest control by altering trophic interactions. Elevated carbon dioxide (CO2) concentrations can reduce host plant quality and, in turn, alter herbivore and natural enemy preference and performance. Using the Geisenheim VineyardFACE (free-air carbon dioxide enrichment) facility, we studied plant- and herbivore-mediated bottom-up effects of elevated CO2 concentration on the European grapevine moth, Lobesia botrana, and the parasitoid Trichogramma cacoeciae. Grapevine inflorescences of two cultivars cultivated at ambient or elevated CO2 (aCO2 and eCO2: 400 and 480 ppm) in the VineyardFACE were incorporated into L. botrana artificial diet. Eggs laid by the respective adults were parasitized by T. cacoeciae. Egg size and emergence rate of L. botrana as well as parasitism rate, parasitoid emergence rate and egg size preference of T. cacoeciae were evaluated. We observed an indirect grapevine cultivar-dependent bottom-up effect of CO2 on both herbivore and egg parasitoid. Compared to aCO2, eCO2 resulted in larger host eggs and higher parasitism rates regarding Riesling-feeding but not regarding Cabernet Sauvignon-feeding L. botrana larvae. Parasitoid emergence rate was higher when L. botrana had fed on Riesling compared to Cabernet Sauvignon-diet. Egg size preference depended on the host’s diet: T. cacoeciae preferred larger L. botrana eggs when the larvae had fed on grapevine-containing diet but not when they fed on standard artificial diet. Our results highlight the importance of the host’s diet for the parasitoid’s preference and performance. They furthermore suggest that the future efficiency of L. botrana-biocontrol by T. cacoeciae will not decrease under elevated CO2 concentrations.

Modeling Root-Knot Nematode Regulation by the Biocontrol Fungus Pochonia chlamydosporia.

Two models of increasing complexity were constructed to simulate the interactions between the root-knot nematode (RKN) Meloidogyne incognita and the biocontrol fungus Pochonia chlamydosporia var. catenulata in a rhizosphere microcosm. The models described discrete population dynamics at hourly rates over a 6-month period and were validated using real parasitism and nematode or fungus data. A first, general Pochonia-nematode-root model (GPNR) used five functions and 16 biological constants. The variables and constants describing the RKN life cycle included the rates of egg production, hatching, juvenile (J2), and mature female development, including root or nematode self-density-dependent factors. Other constants accounted for egg parasitism, nematode-induced root losses, growth, and mortalities. The relationship between nematodes and fungal propagules showed density dependence and cyclic variations in time, including an attractor on the propagules and J2 phases space. The simulations confirmed a P. chlamydosporia optimal initial density of 5 · 103 propagules · cc soil-1, as usually applied in assays. The constants used in GPNR showed adherence to the nematode biology, with 103 eggs per egg mass, a 10-day average lifespan of J2, with 2 days required to enter roots, and adult lifespan lasting 24 days. The fungus propagule lifespan was 25 days, with an average feeder root lifespan lasting around 52 days. A second, more complex Pochonia-nematode-root detailed model (GPNRd) was then constructed using eight functions and 23 constants. It was built as GPNR did not allow the evaluation of host prevalence. GPNRd allowed simulations of all RKN life stages and included non-parasitic and parasitic fungus population fractions. Both GPNR and GPNRd matched real J2 and fungus density data observed in a RKN biocontrol assay. Depending on the starting conditions, simulations showed stability in time, interpreted as effective host regulation. GPNRd showed a fungus cyclic relationship with the J2 numbers, with prevalence data close to those observed (38.3 vs. 39.4%, respectively). This model also showed a further density-independent nematode regulation mechanism based on the P. chlamydosporia switch from a non-parasitic to a parasitic trophic behavior. This mechanism supported the biocontrol of M. incognita, also sustained by a concomitant increase of the root density.

Monitoring the impact of introduced emerald ash borer parasitoids: factors affecting Oobius agrili dispersal and parasitization of sentinel host eggs

Monitoring the impact of introduced emerald ash borer parasitoids: factors affecting Oobius agrili dispersal and parasitization of sentinel host eggs

Representatives of Lepidoptera groups in the biotecenosis of Uzbekistan and their effective parasite-entomophage types

In this article, we traced the development of fauna, bioecology and populations of more than 50 species of the main family Lepidoptera, found in the biocenosis of Uzbekistan. Research has been conducted in agricultural crops, forestry and natural biocenoses, and representatives of the Lepidoptera family have been involved in scientific research on species that cause great economic damage. Trichogrammatidae, Braconidae, Ichneumonidae, Chalcididae, Pteromalidae, and Tachinidae, the main entomophagous species that effectively control the number of members of the Lepidoptera family, have also been identified and systematically analyzed. The representatives of the family Trichogrammatidae, which are effective parasitic entomophagous in the management of the number of representatives of the family Lepidoptera. The study revealed that in the agrobiocenoses of cotton, mung bean, corn and cabbage in Tashkent province, the level of occurrence of three main species of nightshade pests of the family Trichogrammatidae, which are egg parasites of the family Lepidoptera, was determined. This means that the number of nights can be effectively controlled by members of the trichogramma family.

Natural Egg Parasitism by Scelionidae on a Phycitine Cactus Moth in Mexico

La detección de enemigos naturales nativos que pueden utilizar a Cactoblastis cactorum como hospedero, es relevante tras su invasión a Norteamérica. Detectamos avispas (Scelionidae) parasitando huevos de Melitara cf. junctolineella (una polilla del cactus en Phycitini estrechamente relacionada con C. cactorum) en Bustamante, Nuevo Leon, noreste de México. Este es el primer reporte de Scelionidae parasitando huevos de polillas del cactus (Phycitini). Debe investigarse la capaci-dad de esta avispa para parasitar los huevos de C. cactorum.

Biological Control Options for the Golden Twin-Spot Moth, Chrysodeixis chalcites (Esper) (Lepidoptera: Noctuidae) in Banana Crops of the Canary Islands.

Simple SummaryThe golden twin-spot moth, Chrysodeixis chalcites, is a pest whose larvae cause serious skin injuries to banana fruits in the Canary Islands, reducing their commercial value. The use of Integrated Pest Management (IPM) strategies (cultural, biological, and chemical control) is recommended for the effective and sustainable management of this pest. The identification of its parasitoids and the quantification of their effects on pest populations are essential for the development of biological controls. In this study, we conducted an extensive survey to identify the most important parasitoid species of Ch. chalcites and evaluated the efficacy of the egg parasitoid Trichogramma achaeae as a biological control agent in banana plantations in the Canary Islands. Our findings indicate that populations of native parasitoids can exert a certain degree of natural control over Ch. chalcites. However, their naturally occurring populations are insufficient to minimize the damage caused by this pest. Thus, the development of IPM programs based on the use of selective insecticides, the conservation of natural enemies and inundative releases of mass-reared wasps is also necessary. The parasitoid T. achaeae has been identified as a promising biological control agent of Ch. chalcites in greenhouse banana crops, but it is necessary to carry out further studies to establish the most appropriate release strategies.Chrysodeixis chalcites (Esper) (Lepidoptera: Noctuidae) is a significant pest in banana plantations in the Canary Islands. Field surveys were carried out to identify its naturally occurring parasitoids and estimate their parasitism rates between September 2007 and October 2010. Ch. chalcites was parasitized by six different larval/pupal parasitoid species: Cotesia sp., C. glomerata L. (Hym.: Braconidae), Aplomyia confinis Fallén (Dip.: Tachinidae), Hyposoter rufiventris Perez, Ctenochares bicolorus L. (Hym.: Ichneumonidae) and Aleiodes sp. (Hym.: Braconidae). Among them, Cotesia sp. was the most frequent species, accounting for 8.18% of parasitized larvae. High levels of egg parasitism were detected, with Trichogramma achaeae Nagaraja and Nagarkatti (Hym.: Trichogrammatidae) being the most widely distributed egg parasitoid. A greenhouse assay was also carried out on a commercial banana crop with the aim of evaluating the potential of T. achaeae as a biological control agent and compared with a chemical control. Five periodic inundative releases of 35 adults/m2 every 21 days were necessary to achieve an adequate parasitism level (56.25 ± 1.61%). Moreover, there was 15.75% less foliar damage in the biological control plot compared to the chemical control plot. These results indicate that T. achaeae could be a promising biocontrol agent of Ch. chalcites in greenhouse banana crops.

Strategy of Nematophagous Fungi in Determining the Activity of Plant Parasitic Nematodes and Their Prospective Role in Sustainable Agriculture.

In this review, we supply a framework for the importance of nematophagous fungi (nematophagous fungi [NF]) and their role in agricultural ecosystems. We characterize the taxonomy, diversity, ecology, and type of NF, depending on their interaction with plant-parasitic nematodes (PPNs). We described potential mechanisms of NF in the control of PPNs, the efficiency and methods of utilization, and the use of nematicides in sustainable agriculture. We explain the utilization of NF in nanotechnology as a new approach. NF are significant in the soil for having the effective potential for use in sustainable agriculture. These types of fungi belong to wide taxa groups, such as Ascomycota, Basidiomycota, and other groups. Diverse NF are available in different kinds of soil, especially in soils that contain high densities of nematodes. There is a relationship between the environment of nematodes and NF. NF can be divided into two types according to the mechanisms that affect nematodes. These types are divided into direct or indirect effects. The direct effects include the following: ectoparasites, endoparasites, cyst, or egg parasites producing toxins, and attack tools as special devices. However, the indirect effect comprises two groups: paralyzing toxins and the effect on the life cycle of nematodes. We explained the molecular mechanisms for determining the suitable conditions in brief and clarified the potential for increasing the efficacy of NF to highly impact sustainable agriculture in two ways: directly and indirectly.

Trait‐based characterisation of parasitoid wasp communities in natural and agricultural areas

Abstract Life‐history traits are increasingly used to understand how arthropod communities assemble and function under diverse conditions, for example why some species are better adapted to agricultural intensification than others. We aimed to understand which traits characterise parasitoid wasps under agricultural disturbances. To this end, we studied parasitoid communities from pomegranate orchards and nearby natural habitats in Israel. Ten sites along a climate gradient were sampled thrice along one fruit‐growing season. We compiled information on life‐history traits associated with development, adult diet and host taxa, for 27 well‐represented parasitoid species. We tested for relationships between the parasitoids' abundances, functional traits and environmental conditions, using RLQ and fourth‐corner analyses. Life‐history traits were highly related to environmental variables. Koinobionts (wasps whose parasitized hosts feed and grow), and parasitoids of aphids and whiteflies, were more common, and sugar‐feeding was less common, in orchards than in natural habitats. Parasitism of larval hosts correlated with aridity, while egg parasitism increased with herbaceous vegetation cover. Host composition and koinobiosis shape parasitoid communities in the orchards. Koinobiosis is often associated with life‐history traits such as small eggs, short life‐span, early egg maturation and high fecundity, which may be adaptive in the frequently disturbed orchard habitats. Further, dense vegetation conditions seem to favour egg parasitism (perhaps because of reduced risks of egg desication), while larval parasitism is more common in arid seasons and sites. These findings provide initial insights regarding the effects of land use and climate on the functional characteristics of parasitoid communities.

Effect of Rhizoglomus fasciculatum and Paecilomyces lilacinus in the biocontrol of root-knot nematode, Meloidogyne incognita in Capsicum annuum L

ABSTRACT Root-knot nematodes possess a major threat to agricultural production of various crops worldwide. The intensive use of chemical nematicides to control plant parasitic nematodes has adverse effects on our environment and human health. Owing to the importance of developing new strategies, an experiment was conducted to reveal the influence of arbuscular mycorrhizal fungus, Rhizoglomus fasciculatum and nematophagous fungus, Paecilomyces lilacinus alone or in combination with various organic amendments such as superphosphate, green and organic manure to control the infection of root-knot, nematode Meloidogyne incognita in a vegetable crop Capsicum annuum. These two fungi along with soil amendments significantly improved plant growth and fruit yield and effectively controlled infection of M. incognita. The dual inoculation of P. lilacinus and R. fasciculatum reduced the number of galls and egg masses, thereby revealing the controlled proliferation of M. incognita infection in C. annuum roots. The beneficial effect of these fungi further increased on supplementation of soil with organic or green manures. Inoculation of C. annuum with these two fungi showed a significant increase in egg parasitization; however, maximum effect was detected on dual inoculation. Amongst the soil amendments, the best response was obtained in case of green manure along with mycorrhizal fungus and P. lilacinus. Present study revealed that nematophagous and AM fungi, in combination with green manure were effective in controlling M. incognita, thus suggesting the use of such agents for biocontrol of plant parasitic nematodes in agriculture.

Field performance of the egg parasitoid Trichogramma cacoeciae Marchal (hymenoptera: Trichogrammatidae) following releases against Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae) in two types of oasis in Tunisia

This study was carried out in two oases located in the south-west of Tunisia to investigate the efficacy of the oophagous parasitoid Trichogramma cacoeciae against Ectomyelois ceratoniae on date palm trees. The first oasis (Hezoua) is characterized by a cropping system divided into three levels of cultures. In the second oasis (Douz), orchards were based on the monoculture of the Deglet Noor cultivar. Parasitoids were released with three doses 26,000, 36,000 and 46,000 Trichogramma/ha. The impact of Trichogramma releases was evaluated by monitoring the egg parasitism, male catches of E. ceratoniae through pheromone traps, fruit damage during the whole season and fruit infestation at harvest. Trichogramma cacoeciae accomplished higher egg parasitism in Hezoua oasis (19.71 ± 1.02%) as compared to Douz oasis (8.43± 1.03%). Inundative releases of T. cacoeciae in the two oases resulted in varying degrees of pest control and they were not sufficient to limit economic losses.

Interactions between Rice Resistance to Planthoppers and Honeydew-Related Egg Parasitism under Varying Levels of Nitrogenous Fertilizer.

Simple SummaryPlanthopper outbreaks in rice are associated with excessive fertilizer applications. Public research has focused on developing resistant rice to combat these outbreaks. However, to preserve ecosystem resilience, natural enemy efficacy should be maintained on resistant and susceptible rice. We examined the impact of egg parasitoids on planthoppers (Nilaparvata lugens (Stål) [BPH] and Sogatella furcifera (Horváth) [WBPH]) and a leafhopper (Nephotettix virescens (Distant) [GLH]) in field plots of resistant (IR62) and susceptible (IR64) rice under low and high nitrogen. GLH and WBPH were more abundant in low-nitrogen plots during dry (GLH) and wet (GLH, WBPH) season sampling at an early crop stage. GLH were also more abundant on IR64. Parasitoids killed between 24 and 52% of planthopper eggs during exposures in trap plants. Parasitism by Oligosita and Anagrus wasps was higher on IR64 (BPH eggs) and in high-nitrogen plots (Oligosita spp. on BPH and WBPH eggs; Anagrus spp. on BPH eggs). Parasitism by Anagrus spp. was associated with the presence of honeydew and was highest where honeydew was derived from BPH feeding on IR62; these effects were only observed under high nitrogen. Results suggest that honeydew from IR62 favors parasitoids when plants are most vulnerable (i.e., under high nitrogen), thereby countering nitrogen-induced declines in host resistance.Host plant resistance is the most researched method for the management of planthoppers and leafhoppers in tropical rice. For optimal effects, resistance should be resilient to fertilizer inputs and work in synergy with natural enemies. In field plot experiments, we examined how rice resistance and fertilizer inputs affect mortality of planthopper and leafhopper eggs by hymenopteran parasitoids. We used IR62 as a variety with resistance to Nilaparvata lugens (Stål) [BPH], Sogatella furcifera (Horváth) [WBPH] and Nephotettix virescens (Distant) [GLH], and IR64 as a susceptible control. The herbivores were more abundant during wet season sampling in low-nitrogen plots. During this study, parasitoids killed between 31 and 38% of BPH eggs and 24 and 52% of WBPH eggs during four days of field exposure. Parasitism, mainly due to Oligosita spp., was generally higher in high-nitrogen and IR64 plots. Similar densities of eggs in exposed plants suggest that these trends were mediated by semiochemicals and therefore support the Optimal Defense Hypothesis. Honeydew from BPH on IR62 had more xylem-derived wastes than honeydew on IR64. We applied honeydew from both varieties to sentinel plants. Parasitism by Anagrus spp. was higher on plants of either variety treated with honeydew derived from IR62; however, the effect was only apparent in high-nitrogen plots. Results suggest that Anagrus spp., by responding to honeydew, will counter the nitrogen-induced enhancement of planthopper fitness on resistant rice.

Sensitivities to Chill Durations and No-Chill Temperatures Regulating Eclosion Responses Differ Between Rhagoletis zephyria (Diptera: Tephritidae) and its Braconid Parasitoids (Hymenoptera: Braconidae).

Seasonal temperatures select for eclosion timing of temperate insects and their parasitoids. In western North America, the fruit fly Rhagoletis zephyria Snow (Diptera: Tephritidae) is parasitized by the hymenopterous wasps Utetes lectoides (Gahan), an egg parasite, and Opius downesi Gahan, a larval parasite (both Braconidae). Eclosion of wasps should be timed with the presence of susceptible fly stages, but reports indicate U. lectoides ecloses in the absence of flies under no-chill conditions. Based on this, we tested the hypotheses that chill durations and no-chill temperatures both differentially regulate eclosion times of R. zephyria and its parasitic wasps. When fly puparia were chilled at ~3°C for 130-180 d, U. lectoides and O. downesi always eclosed on average later than flies. However, after 180-d chill, flies eclosed on average earlier than after 130- and 150-d chill, whereas eclosion times of U. lectoides and O. downesi were less or not affected by chill duration. When fly puparia were exposed to 20-22°C (no chill), U. lectoides eclosed before flies, with 88.9% of U. lectoides versus only 0.61% of flies eclosing. Taken together, findings show that eclosion times of flies are more sensitive to changes in chill duration than those of wasps. Flies are less sensitive than wasps to no-chill in that most flies do not respond by eclosing after no-chill while most wasps do. Our results suggest that shorter winters and longer summers due to climate change could cause mismatches in eclosion times of flies and wasps, with potentially significant evolutionary consequences.

The Impact of Microbial and Botanical Insecticides on Grape Berry Moths and Their Effects on Secondary Pests and Beneficials

According to the European Directive 2009/128/EC and the subsequent provisions activated in member states, conventional pesticides should be progressively replaced by “non-chemical tools and/or measures”. The identification of reliable alternatives to pesticides is crucial to achieve this objective. A European project (PURE) was funded to investigate this topic with reference to annual and perennial crops. In this framework, a number of natural insecticides, in particular microbial and botanical ones (Bacillus thuringiensis ssp. kurstaki, Beauveria bassiana, azadirachtin, pyrethrins and spinosad) were selected to test their effectiveness against grape berry moths, the key pests in most European vineyards. Trials were conducted in 2011 and 2012 in two experimental vineyards located in Italy (Tuscany and Veneto regions), following a randomized block design. Additional investigations were carried out in the Veneto region during 2013. Trial results stressed the high performance of spinosad and B. thuringiensis in controlling berry moth densities and the related damage. The use of B. bassiana mixed with B. thuringiensis did not significantly improve the impact of B. thuringiensis alone. Azadirachtin, and especially pyrethrins, proved to be less effective on berry moths than previous insecticides. The use of selected insecticides caused side-effects on a number of secondary pests, in particular leafhoppers. In 2011, densities of Empoasca vitis were higher in spinosad-treated plots probably because of a reduced egg parasitization rate. One year later, the population density of Zygina rhamni was higher in the plots treated with spinosad or pyrethrins. This trend was confirmed on spinosad-treated plots in the last experimental year. At the same time, spinosad and pyrethrins significantly reduced the predatory mite populations compared to other treatments. The use of these insecticides in viticulture is discussed in the framework of organic viticulture and Integrated Pest Management (IPM).

Parasitism of Meloidogyne incognita eggs by Native Fungi of Assam

In the current investigation, four fungi viz., Paecilomyces niphetodes, Acremonium falciforme, Fusarium oxysporium, and F. solani were capable of parasitizing Meloidogyne incognita eggs. The high percentage of egg parasitism was recorded by P. niphetodes. Microscopic examinations showed that the hyphae of P. niphetode, A. falcifrome, F. oxysporum and F. solani were closely attached to the egg surface of the parasitized eggs, made perforations, penetrated, ramified, and completely fed upon the internal content of the eggs. The parasitization of the second stage juvenile that emerged from the eggs by P. niphetodes and A. falciforme was seen. Whereas, A. falcifrome, F. oxysporum, and F. solani established as dormant spores inside or outside of M. incognita eggs.

Conserving Floral and Faunal Diversity of Rice Paddies

Rice paddies have complex trophic food webs of flora and fauna. Integrated biodiversity management of flowering forbs can help conserve the beneficial insects of rice ecosystem, in turn enhancing natural biological control of pests. A concept of habitat management through ecological engineering has been developed at the ICAR-Indian Institute of Rice Research, tested, and validated in farmers’ fields over several seasons of crop. The strategies are low cost, easy to adopt, ecological sound and environmentally friendly, while providing farmers with monetary returns and nutritional benefits. One of the techniques advocated, is increasing floral diversity. Floral diversity can be maintained by conserving commonly occurring flowering forbs in rice fields or by growing a crop plant that provides monetary and nutritional benefits. Flowering plants on rice bunds had significant impact on biodiversity of parasitoids such as Anagrus, Oligosita and others. Field studies through baiting and laboratory studies for longevity indicated enhanced parasitization rates and six to ten times increase in longevity of parasitoids. Significant differences were observed in parasitism of hopper eggs in plots with different crop borders in comparison to plots without flower borders (F= 4.91; df 7; p <0.01).

New insights on the impact of earthworm extract on the growth of beneficial soil fungi: species-specific alteration of the nematophagous fungal growth and limitation of an entomopathogenic fungus

Earthworms influence soil ecosystem functions such as decomposition and regulation of nutrient cycles by burrowing, feeding, or secreting their cutaneous excreta. Earthworms can also modulate soil biodiversity and their interactions. Recent research has revealed that earthworm feeding activity or excretions can alter the performance of entomopathogenic nematodes (EPNs) and entomopathogenic fungi (EPFs), known biological control agents. Still, the impact of earthworm cadavers on the growth and reproduction of other biological control agents such as nematophagous fungus (NFs) and EPFs has been poorly explored. We suggest that earthworm body tissue could be used as a food supply by certain fungal species. We hypothesize that fungi with a high adaptive capacity as pathobionts such as NF will use earthworm cadavers to a certain extent, while the growth and reproduction of fungi with limited or specific nutrition needs, such as EPFs, will be restricted. In this study, we evaluated two NF species: a nematode-trapping fungus Arthrobotrys musiformis Drechsler (Orbiliales: Orbiliaceae) and a nematode egg or cyst parasite Purpureocillium lilacinum (Thom) (Hypocreales: Ophiocordycipitaceae), and one EPF species: Beauveria bassiana (Balsamo). We exposed each fungus to two different Aporrectodea molleri extract media at six concentrations in agar medium (n = 3 per treatment) and liquid medium (n = 5): (i) earthworms devoid of intestinal contents (EDG) (C1...C6), and (ii) fresh earthworms (FE) (C1...C6). The use of FE and EDG was designed to discriminate the effect of earthworms? intestinal content on fungal growth. These treatments were also compared to alternative conventional media potato dextrose agar (PDA) and brain heart infusion (BHI) as the positive controls. We evaluated the vegetative growth capacity daily for 18 days, registering the reproduction at the end of the experiment. We observed that EPF B. bassiana did not grow in FE and EDG solid medium but showed germination in their liquid media. However, both NF species could grow and reproduce in both media but following a species-specific pattern. In all cases, FE and EDG reduced fungal growth compared to PDA and BHI. Our results suggest that the use of earthworm as a resource in natural conditions might depend on the expected specialization, with EPF B. bassiana with the lowest use, NF A. musiformis moderately, and P. lilacinum widely used. The study illustrates the complexity of the soil organisms? interactions and highlights the necessity to advance the understanding of the contribution of all the beneficial soil organisms in a comprehensive manner.