Indigenous Predators Research Articles

Increasing the Growth of Bridal Tears Flower Stem Cuttings (Antigonon leptopus) by providing Plant Growth Regulators and Planting Media

It is imperative to implement integrated control measures for Oil Palm Leaf-Eating Caterpillars (UPDKS), as continual chemical management can result in pest resistance and environmental degradation. Utilizing natural enemies for biological control involves the utilization of predators, pest-consuming animals, as well as parasites or bacteria with pathogenic properties against pests. Examples of predators, including Sycanus leucomesus and Eocanthecona furcellata, egg parasitoids, such as Trichogrammatidea thoseae, and larval parasites, such as Chaetexorista javana, are a few of the many types of organisms that can have an impact on the populations of their prey. These indigenous predators sustain themselves by feeding on host plants within their natural habitat. The bridal tears flower (Antigonon leptopus) is considered to be one of the host plants. Thus, it is imperative to promote the growth of Antigonon leptopus in order to provide a habitat for the natural predators of the UPDKS pest. The objective of this research was to identify the components of the planting medium and to establish the most effective concentration of growth regulators for propagating bridal tears stem cuttings (Antigonon leptopus). The research was conducted at the Indonesian Palm Oil Technology Institute (ITSI) Practice Garden in Medan, North Sumatra. The research was conducted over three months, from February to April 2024. The Factorial Randomized Block Design (RAK) method was employed, with the first factor, namely S (Planting Media), comprising three levels: Top Soil without solid, Top Soil with 20% Solid, and Top Soil with 40% Solid. The second factor, namely Plant Growth Regulators, was also treated with three levels: without plant growth regulators, concentration of 100 Mg/l, and concentration of 200 Mg/l. Thus, the study comprises nine treatment combinations, each with four replications. The analysis of variance (ANOVA) table is employed to assess the significance of the observed differences, with the Duncan multiple range test (DMRT) conducted at a 5% level of significance when warranted.The findings from the research indicated that the manipulation of the planting medium composition (S) had a notable impact on the number of leaves, number of roots, and fresh weight of the roots. Additionally, it was found to have a highly significant influence on the height of the shoots. The optimal composition of the planting medium was identified as S2. The manipulation of growth regulators (R) concentration had a notable impact on shoot height and root fresh weight, as well as a highly significant effect on the number of leaves and roots. R2 exhibited the most optimal concentration of growth regulators. The growth of Antigonon leptopus stem cuttings was not affected by the combination of planting medium composition (S) and growth regulator concentration (R) in a non-interacting manner.

Physio-metabolic alterations in Labeo rohita (Hamilton, 1822) and native predator Chitala chitala (Hamilton, 1822) in presence of an invasive species Piractus brachypomus (G. Cuvier, 1818).

A 60days study was conducted to evaluate the physiological response of indigenous species Labeo rohita (LR) and indigenous predator Chitala chitala (CC) in presence of an invasive species Piaractus brachypomus (PB). Two treatment groups as LR + PB (T1) and LR + PB + CC (T2) with individual control groups as T0LR, T0PB and T0CC were designed in triplicates. Fingerlings of LR, PB and CC were randomly distributed into 15 circular tanks with a stocking ratio of 1:1 and 1:1:0.3 in T1 and T2 group, respectively and 10 nos. each of LR, PB and CC in respective control groups. At first 15min of the experiment, cortisol level was found significantly (P < 0.05) higher in all three experimental fishes in T1 and T2 groups. With the experimental duration, the level of stress hormone (cortisol), oxidative stress enzymes (superoxide dismutase, catalase, and glutathione peroxidase), tissue metabolic enzymes (lactate dehydrogenase and malate dehydrogenase), serum metabolic enzymes (transaminase enzymes) and blood glucose level were significantly (P < 0.05) increased in T1 and T2 groups for LR and CC whereas, no variation (P > 0.05) were observed for PB in both T1 and T2 groups. The total antioxidant capacity (TAC), liver glycogen, total protein, albumin and globulin were found to be significantly (P < 0.05) decreased in LR in the presence of PB and CC. The present study provides a preliminary insight into the biological interaction between native and invasive species and their physiological responses in the presence of native predator with higher trophic index. Thus, the results of the study suggest the superior traits of invasive P. brachypomus try to dominate the other two native species by negatively influencing the native fauna even with a higher trophic index (C. chitala).

Problems and perspectives for the use of exotic predators and parasitoids in biological control

The accidental introduction of alien organisms potentially harmful to agriculture can cause extensive damage to vegetable crops and fruit plants and is favoured by the global mobility of people, trade of goods and the ongoing climate change. The use of alien predators and parasitoids is well known in the agricultural field, where they are often used for biological control to protect fruit and horticultural plants. The management of invasive species is and will be one of the key issues for preserving biodiversity and the profitability of crops, the latter can now count on an effective, consolidated and lasting strategy: Integrated Pest Management (IPM). The legislation on this subject is complex and articulated and is continuously being updated. It allows for the development of specific skills in biological control and the availability to use quarantine chambers where it is possible to breed and study the behaviour of antagonists (predators and parasitoids), even exotic ones. If successful, their subsequent release to targeted biological control interventions of infestations of the IAS ‘Invasive Alien Species’ can be carried out. This contribution highlights the risk that such practices may involve and takes into account the following points: 1. The behaviour of an alien species can be very different in different contexts, being able to be a real IAS or not showing any character of invasiveness; 2. The behavior of an alien species can vary over time in the same context, diversifying and also expanding its trophic niche; 3. A good number of indigenous predators and parasitoids can over time adapt to new alien prey/hosts and could potentially be used for biological control. In future, biological control will be increasingly used given that EU funds reward and support this type of approach and the intentional introduction of alien natural predators and parasitoids into agroecosystems, although subject to strict protocols, cannot exclude spontaneous colonization by these last of natural environments with currently not assessable consequences on their biocoenosis. In conclusion, the rigorous risk analysis alone does not currently seem sufficient to exclude potential damage to local biodiversity, and programs for the release of exotic predators and parasitoids should be associated with mandatory monitoring of at least five years to verify the behaviour of these aliens in nature and their possible impact on ecosystems.

Enhancing Coccinella Beetle Biological Pest Control via a Floral Approach in Cucumber Greenhouse.

Flower-rich habitats are crucial for promoting biodiversity and ecosystem services within agricultural ecosystems, such as pollination and pest control. The present study investigates the efficacy of employing floral structures as a criterion for the selection of plant species in order to enhance the attraction of natural enemies within cucumber greenhouses, consequently augmenting floral resources. The results of our study provide evidence that flower strips have a beneficial effect on the fitness of critical natural predators, while not facilitating the proliferation of detrimental insect species. These findings exhibit potential for enhancing pest-management services in the agricultural sector. The findings of our study demonstrate that pest levels within greenhouse environments closely resemble those observed in real-world commercial cropping systems. As a result, the introduction of Coccinella septempunctata and Menochilus sexmaculatus biocontrol agents is confirmed to be a reliable and efficient method for pest management. The phenomenon of predator-prey density dependency is recognized as a crucial element in the implementation of biological control strategies. Furthermore, we investigate the impact of floral resources on the reproductive capacity of indigenous predators. The impact of Coriandrum sativum on fertility is substantial, indicating that the presence of a varied plant assortment with overlapping flowering periods can prolong the availability of floral resources. This study highlights the significance of flower-rich habitats and deliberate plant selection in augmenting biodiversity, ecosystem services, and pest management within agricultural settings. The implementation of conservation biological control technologies presents supplementary ecological advantages, thus offering practical implications for the promotion of sustainable agricultural practices.

Study of the population dynamics of phytoseiid mites on citrus under natural conditions

Citrus is the most extensively produced tree fruit crop in the world, and the citrus red mites, Panonychus citri (McGregor) and citrus rust mites, Phyllocoptruta oleivora (Ashmead) are the serious pest mites of citrus crops. Except for chemical control, biological control is an important component of integrated pest management and plays an essential role in regulating populations of pest mites. Predatory mites from the family Phytoseiidae are important natural enemies. The populations of P. citri are usually controlled by indigenous predators, mainly the phytoseiid mites. As native phytoseiids are more likely to adapt to the local environmental conditions than the commercially available phytoseiids, conservation of local phytoseiid species is a key factor for the IPM success in citrus orchards. Investigation into the species and population dynamics of phytoseiid mites in citrus orchards will provide important references to the conservation and utilization of predatory mites. This work aimed to investigate the species of phytoseiid mites and their seasonal population dynamics associated with P. citri in different citrus cultivars orchards. We sampled phytoseiid mites from orchards planted with three citrus cultivars of citron-lemon, Ehime Kashi No. 28 and Shatangju, respectively, from April to December in 2018⁓2021. Species of phytoseiid mites, and their developmental stage and gender were identified under a microscope. In the citron-lemon orchard, we recorded nine phytoseiid species in 2018, but only three species in 2019. The dominant species was Scapulaseius newsami (Evans). In 2020, five species with a dominant species of Euseius nicholsi (Ehara et Lee) were found in Ehime Kashi No. 28 orchard, but only two with a dominant species of Neoseiulus californicus (McGregor) detected in the Shatangju orchard. In the Shatangju orchard in 2021, six species were recorded with N. californicus being dominant from April to July, and Amblyseius eharai Amitai &amp; Swirski being dominant from August to December. The population of predatory mites peaked in May and October in the citron-lemon orchard, and in May, July and October in the Ehime Kashi No. 28 and Shatangju orchards. All active life stages (i.e., larva, nymph and adult) were found and most were adults. The sex ratio was female-biased (over 80%) in each orchard. In conclusion, the population size of phytoseiids changed over the growing seasons. Whether this could be attributed to the different tolerance capacities of different species to the local climate conditions or chemical pesticides remains for future studies.

Intensive Fishing Effort and Market Controls as Management Tools for Invasive Aquatic Species: A Review

Invasive aquatic species may disrupt ecosystems and cause socioeconomic damage. Biosecurity protocols were developed to prevent transport and unintended introductions of invasive species, but less attention has been paid to management once they become established. The use of classical fisheries stock assessment to determine levels at which selectively targeted fisheries elicit recruitment overfishing is discussed. Case studies of several species of invasive aquatic organisms, including lionfish Pterois spp. two species of mytilids and three species of crayfish, including Faxonius rusticus (Girard, 1852), are discussed as examples. Fecundity as measured by egg production rate (EPR) is a key factor determining how the various species react to fishing pressure. Ecosystem modelling of predatorprey relations between indigenous and invasive aquatic species suggests that restricting fishing effort on indigenous predators of invasive prey may be as effective in managing invasive species in lieu of directly increasing fishing effort on the targeted species itself. Invasive mytilids Dreissena polymorpha (Pallas, 1771) and Mytella strigata (Hanley, 1843) may not be effectively controlled by intensive fishing effort due to high EPR values. However, crayfish that brood offspring and exhibit much lower EPR values may be ideal candidates for stock assessment and setting fishing effort targets to promote recruitment overfishing. Recommendations for managing invasive aquatic species include: collecting data on population dynamics of the invasive species; assessing predator populations; developing fisheries that target the invasive species; and collecting socioeconomic data to understand the human dimensions of the impacts of the invasive species and inform subsequent policy development.

Low‐intensity environmental education can enhance perceptions of culturally taboo wildlife

AbstractTraditional cultural beliefs influence perceptions of animals and can result in persecution of wildlife. In Africa, stigmas against species associated with witchcraft can act as a barrier to the uptake of sustainable practices such as reducing crop damage through reliance on indigenous predators rather than pesticides to control rodent agricultural pests. One way of enhancing perceptions of wildlife to increase participation in ecologically based rodent management schemes is through environmental education. Low‐intensity programs can produce positive attitudinal shifts, but their impact has not been assessed for species strongly associated with witchcraft. We tested whether a presentation on the natural history of owls in the Limpopo Province of South Africa could improve perceptions of these species and increase willingness to participate in the installation of owl boxes to increase owl populations and reduce rodent populations and crop damage. We used a pre‐ and post‐survey to assess the perceptions of owls of 340 learners aged between 12 and 18 in four schools before and after listening to the presentation. Respondents that watched the presentation had more positive perceptions of owls than those that had not watched the presentation and were more willing to put up owl boxes near their home. Despite this shift, negative perceptions of owls still dominated responses due to cultural associations with the occult. These findings indicate that even low‐intensity programs can be effective at enhancing perceptions of taboo wildlife. We suggest that environmental education programs featuring culturally taboo species should adopt a culturally sensitive approach to focus on the benefits these species provide.

Spatial and temporal variability in the diet of Pacific marten (Martes caurina) on Haida Gwaii: an apex predator in a highly modified ecosystem

Knowledge of the diet ecology of apex predators in insular island ecosystems has direct applications to the conservation of endemic species at risk of extinction. We used stable isotopes of carbon and nitrogen to infer resource-use strategies of an indigenous predator, the Pacific marten (Martes caurina (Merriam, 1890)), in a highly modified ecosystem on Haida Gwaii, British Columbia, Canada. We used Bayesian isotopic mixing models to estimate the relative contributions of different food sources to marten diet across seasons and during overall lifetime, and to determine how diet varied with different levels of access to marine resources. Isotopes of carbon and nitrogen measured in hair and muscle tissue suggested that marten consumed salmon (3%–17%) and berries (25%–37%) seasonally; these diet groups were relatively minor components of the lifetime diet. Analysis of bone collagen suggested that terrestrial fauna — including birds, deer, small mammals, and invertebrates — contributed the most to diet (41%–55%), and marine invertebrates (38%–48%), not salmon (0%–3%), were the main allochthonous marine nutrient subsidy to lifetime diet. Plasticity in foraging ecology, combined with a broad dietary niche, introduced prey, notably the invasive Sitka black-tailed deer (Odocoileus hemionus sitkensis Merriam, 1898), as well as abundant marine resources, may allow marten to outcompete other indigenous and endemic carnivores on Haida Gwaii.

Predation on the invasive swimming crab Charybdis hellerii (Crustacea, Decapoda) by Myrichthys ocellatus (Actinopterygii, Ophichthidae): the first record of consumption by a native fish

ABSTRACT Charybdis hellerii is an invasive swimming crab widely disseminated in the western Atlantic. This species became a threat to colonized ecosystems, competing with local species for resources. The extension of distribution and increasing population size of C. hellerii has been associated with the scarcity of indigenous predators and cases of predation report octopuses as the main native predators. In this study, we present the first evidence that native fish can consume C. hellerii. 53 individuals of the goldspotted snake eel, Myrichthys ocellatus, were collected at seagrass and macroalgal beds in Pernambuco State, Brazil, and had their stomach contents analyzed. Three juvenile C. hellerii were found along with native prey. Myrichthys ocellatus feeds mainly on small crabs, thus C. hellerii individuals were consumed before reaching sexual maturity. Oppositely to octopuses and other crab predators, M. ocellatus is of little fishing interest and is commonly found in macroalgae beds, seagrass meadows and sandy areas near reefs. Our results suggest that a higher number of carcinophagous taxa may prey on this invasive crab and we emphasize that the conservation of these species is paramount for controlling C. hellerii populations in invaded areas.

Spatial organisation of habitats in agricultural plots affects per-capita predator effect on conservation biological control: An individual based modelling study

A highly advocated approach to enhance pest control by indigenous predators is to add or maintain appropriate non-crop plant habitats in agrosystems. Although the addition of non-crop plant habitats can enhance the number of predators in crop by increasing their food resources or shelter, the effect is often insufficient to reduce pest abundance or damage. A number of explanations were identified in previous studies; the ability of such habitats to enhance predators, in particular, is affected by the spatial organisation of the habitats at the landscape level. Here, we explore how intra-plot spatial patterns of non-crop habitats affect the per-capita predator effect on pest control. We use a spatially explicit and individual-based model to simulate the foraging movements of an earwig-like predator in a banana field. Predator movements within a day were based on a simple non-specific behavioural assumption: movement is a correlated random walk affected by habitats and edges. Population dynamic processes occurring at larger time or spatial scales, such as reproduction and immigration, were not considered. In this model, non-crop habitats added to plots were considered favourable to predators: movements were slower and more sinuous in non-crop habitat than in unfavourable habitats. The intra-plot spatial patterns of the non-crop habitat were built and characterised using landscape ecology concepts and metrics. We found that the per-capita predator effect was strongly affected by a spatial dilution of predators, induced by non-crop habitat addition, but this negative effect could be partially or fully mitigated by the spatial organisation of the non-crop habitat. At the banana plant level, a long edge length between the crop and non-crop habitat can compensate for this dilution effect by reducing the duration of the periods between predator visits to the banana plant. At the plot level, the best plots (i.e., those in which all banana plants were often visited by predators) were those with non-crop strips in the banana plant rows. Overall, the results support the idea that the spatial organisation of non-crop habitats at the plot level, characterised by the metric edge length in particular, can be managed to minimise the negative impact of the dilution effect.

Field studies on occurrence, alternate hosts and mortality factors of Date Palm Mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae)

The occurrence of date palm mite (DPM), Oligonychus afrasiaticus, its association with other mite species and alternate host plants were studied in nine provinces of Saudi Arabia during eight consecutive years (2011–2018). In addition, different mortality factors of DPM during the fruiting season were assessed in Riyadh city. The results showed that all DPM developmental stages were recorded on date palm young-aged fronds as well as grasses growing underneath the trees during off-fruit periods, even in severe winters. Interestingly, DPM was found only on narrow leaf alternate host plant species belonging to the families Arecaceae and Poaceae. Moreover, Hyphaene thebaica, Phoenix canariensis, Cenchrus ciliaris, Dichanthium annulatum, Hilaria sp., Hyparrhenia hirta, Pennisetum ciliarae, P. divisum, Pennisetum sp. and Aeluropus littoralis were reported for the first time as alternate host plants of the DPM. Two phytophagous mites, Eutetranychus orientalis and E. palmatus (Tetranychidae), and the predatory mite Spinibdella cronini (Bdellidae) were found associated with DPM on date fruits. However, the phytoseiid mite Cydnoseius negevi was found on the grasses growing under the trees. Amongst mortality factors, pathogens followed by predators were responsible of deaths in different DPM stages. However, the unknown environmental factors caused maximum mortality of all DPM stages than any other factor. Based on the obtained data, it is suggested that young-aged fronds should be sampled prior to fruit setting for early detection of DPM and consequently should be chemically treated during the off-season. In addition, the alternate host plants as well as date palm trees growing along the roadside should be chemically treated as they may be a source of DPM. Also, more attention should be given to search and conserve indigenous predators which can be used efficiently against DPM. It is anticipated that such data can provide valuable information to improve IPM program for controlling DPM in other regions of Saudi Arabia.

Body size and competitor identity modulate prey consumption and feeding behaviour in a slow-moving benthic predator (Asterias rubens, Linneaus)

Understanding interactive effects of body size and competition on predator-prey relationships is key to predicting shifts in marine communities, particularly under accelerating pace of introductions of non-native species on a global scale. The common sea star, Asterias rubens (Linneaus), is a dominant indigenous predator in rocky subtidal habitats in eastern Canada, affecting community structure through sustained consumption of bivalve prey, mainly blue mussel, Mytilus edulis (Linneaus). Yet, considerable spatial and dietary overlaps with the indigenous rock crab, Cancer irroratus (Say), and introduced green crab, Carcinus maeneas (Linneaus), together with comparatively lower mobility in A. rubens, suggest the latter is poorly fit to compete with both crabs for M. edulis. A laboratory mesocosm experiment was used to examine competitive interactions for variably-sized M. edulis between small and large, 3-week starved A. rubens, and large C. irroratus or C. maenas (in one-on-one sea star versus crab face-offs) from southeastern Newfoundland. Mussel consumption in starved A. rubens, as well as four components of its natural feeding behaviour, were quantified over 75-h trials in relatively cold (~4 to 5.5 °C) seawater representative of the current northern limit of C. maenas' distribution in the northwestern Atlantic. Results showed that starved A. rubens (1) prioritizes consumption, upon contacting mussel prey, over non-feeding activities such as responding to physical contacts initiated by crabs; (2) alters consumption and feeding behaviour under prolonged exposure to C. irroratus; and (3) increases movement in presence of green crab, more so in large than small sea stars. Overall, findings demonstrate that A. rubens' foraging decisions vary ontogenetically and with competitor's identity. Observed differences in consumption and feeding behaviour in A. rubens exposed to familiar (rock crab) or unfamiliar (green crab) competitors also suggest timing and frequency of encounters with competitors have the potential to alter feeding patterns throughout an organism's lifetime.

Field evaluation of indigenous predacious insect, Chrysoperla carnea (Steph.) (Neuroptera: Chrysopidae), fitness in controlling aphids and whiteflies in two vegetable crops

The green lacewing, Chrysoperla carnea (Steph.) (Neuroptera: Chrysopidae), is a generalist predator in its larval stage of most species of soft bodied insect pests, especially aphids, whiteflies, thrips, coccids, and mealy bugs. This predator had been recorded in different regions in Saudi Arabia as indigenous species. The fitness of this indigenous predator for controlling the aphid, Aphis gossypii Glov., and the whitefly, Bemisia tabaci (Genn.), with five and ten releasing rates on sweet pepper and squash plants in the open field was evaluated. The experiments were carried out in Taif region, Saudi Arabia, during the summer of 2017. On squash plants, the reduction was more than 90% after the third predator release of ten larvae per plant for both pests and reached 100% only for the whitefly after six releases. On sweet pepper plants, reduction rates of the aphid and whitefly reached about 90 and 97%, after the second predator release of five and ten larvae per plant, respectively. A 100% reduction was achieved after four releases with five larvae/plant and three releases with ten larvae/plant. The present findings indicate that the releasing rates of five larvae/pepper plant and 10 larvae/squash plant were sufficient for suppressing both B. tabaci and A. gossypii populations.

Effect of constant temperature regimes on the biological parameters of an anthocorid predator Orius tantillus (Motsch)

Experiments were conducted to investigate the effect of different temperature regimes (16, 20, 24, 28, 32 and 36±1 ° C) on the biological and fertility table parameters of Orius tantillus (Motsch.), an efficient indigenous predator of various thrips species in India Temperature influenced the development and reproduction of O. tantillus . Based on the biological parameters, viz. longevity, fecundity and fertility parameters, 24 ° C was recorded to be the optimum temperature for rearing O. tantillus . The temperature of 16 ° C had a detrimental effect on nymphal survival, while 36 ° C on fecundity. Thus, 16 and 36 ° C were recorded as unsuitable for rearing O. tantillus . The lower threshold temperatures for development of eggs and nymphs of O. tantillus were 8.66 and 6.92 ° C, respectively, indicating that the eggs are more heat-sensitive than the nymphs. Based on the T 0 values, O. tantillus appears to be less heat sensitive in comparison to other Orius spp. The information generated through this study could be used for further improving the standardized production protocol for O. tantillus and also for planning and timing field releases to target thrips species.

Biological control by (Coccinella algerica, Kovar 1977) against the puceron of crops under greenhouses (station bioressources of El Outaya Crstra) Biskra; Algeria

Inputs from chemicals, particularly pesticides, to control crop pests have adverse effects on soil and the environment, among others. To reduce pest attacks, biological control with indigenous predators is the alternative and the cleanest, most environmentally friendly and ecologically balanced way. In order to achieve this objective, we carried out ladybird breeding and releases were carried out on vegetable crops under glass in the Bioressources (CRSTRA) station where chemical inputs are not used. This study shows that massive and successive releases larvae Coccinella algerica stage L3 and L4 (10 to 20 larvae C.algerica and » 350 individuals in Individuals in adult stage / infested plants) reduced effectively the population of aphids.

Suitability of four different prey species for Dichochrysa tacta (Neuroptera: Chrysopidae)

ABSTRACTThe prey suitability for generalist insect predators is an important factor in efficient mass rearing. This work constitutes the first biological study of the predatory lacewing Dichochrysa tacta. We tested the effects of four different prey species on the biological parameters of the predatory lacewing D. tacta under laboratory conditions. These prey species consisted of Ephestia kuehniella (Zeller) and the aphids: Aphis fabae, Aphis punicae and Macrosiphum rosae. The results showed that prey species elicited a significant effect on preimaginal development times, survival, adult longevity and fecundity. In contrast, the progeny sex ratio, egg hatch and egg duration were not significantly affected by prey species. Eggs of E. kuehniella were the most suitable prey among those tested, and led to high survival rates, short development times for the preimaginal stages, long adult longevity, high fecundity, highest intrinsic rate of increase (rm) and highest net reproductive rate (R0) of D. tacta. Nymphs of both A. punicae and M. rosae were also relatively favourable prey, whereas nymphs of A. fabae were less suitable and resulted in reduced development, survival, adult longevity, fecundity, rm and R0. These results could be useful for optimising the mass rearing of D. tacta as an indigenous predator and for understanding its population dynamics in relation to different prey species in the field.

Investigations on the predation of Coccinella septempunctata on Macrosiphum rosae under laboratory conditions

To evaluate the predatory efficacy of Coccinella septempunctata on rose aphid (Macrosiphum rosae), a lab experiment was escorted at 27C at laboratory of Systematics and Entomology, University of Gujrat, Gujrat during 2016. C. septempunctata is one of the most common indigenous predators of the sucking insect-pests such as aphids. Effect of some commonly used insecticides like imidacloprid and clothianidin (telsta) was tested. Mortality of adult C. septempunctata at 24 and 48 h was observed. Clothianidin was a bit more toxic insecticide as compared to imidacloprid with LC 50 value of 0.039593 ppm and LC 90 value of 0.145805 ppm. Results showed that maximum mortality i. e. 100.00% occurred at 48 h by using 0.7% concentration of telsta. While mortality rate was 75.00% at 48 h by using 0.7% concentration of imidacloprid. So, we can say that telsta is more toxic. Minimum mortality i. e. 8.3333% occurred at 24 h by using 0.1% concentration of telsta. While mortality rate was 12.500% at 24 h by using 0.1% concentration of imidacloprid.

The formicid ant, Plagiolepis sp., as a predator of the coffee twig borer, Xylosandrus compactus

The coffee twig borer (Xylosandrus compactus Eichhoff) is an economically important pest of Robusta coffee in Uganda. In this study, a formicid ant, Plagiolepis sp., found in X. compactus galleries at the National Coffee Research Institute in 2014, was evaluated for potential to provide biological control of the twig borer. In a Petri dish feeding bioassay, Plagiolepis sp. preyed on all stages of X. compactus except adults within 24h. In field bioassays where Plagiolepis sp. was caged over X. compactus-infested twigs for one month in muslin sleeves, the predator colonized pest galleries and eliminated all life stages of X. compactus as opposed to the untreated control. In a survey of Plagiolepis sp. in 11 districts of eastern, central and western Uganda, the ant was present in nine of the districts with highest levels of colonization (over 18%) of X. compactus galleries in Luwero district in the central Lake Victoria crescent agroecological zone. These results appear to confirm that Plagiolepis sp. is an indigenous predator of X. compactus which invades pest galleries and feeds on the pest in the field. For prospective utilization of Plagiolepis sp. as a biological control agent of X. compactus, studies on the biology of Plagiolepis sp., its mass rearing protocols and factors favoring its proliferation in the field are highly recommended.

Nesidiocoris tenuis (Reuter) (Heteroptera: Miridae), a predatory species of the tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in Iran

Abstract The tomato leafminer, Tuta absoluta (Meyrick), is a major worldwide pest of tomato crops, both in the greenhouse and in open field cultivations. Since this pest’s new introduction in Iran, it has caused extensive damage. Chemicals have mainly been used to control this pest. The purpose of our research was to identify the indigenous predators of the tomato leafminer, associated with tomato in the Borazjan region of the Bushehr province, Iran. From March to May 2014, infested tomato leaves were collected from protected tomato crops. A predator species from the family Miridae was found, reared, and identified as Nesidiocoris tenuis (Reuter 1895). This species is reported for the first time on tomato leafminer in Iran. Identification of important natural enemies provides a scientific basis for including these predators in the biological programs against this pest.

Indigenous generalist predators and plant residues: conservation biological control of pests in an organically managed cabbage field

Plant residues are viewed as an important source for organic matter in farmlands. We studied if wheat straw and weed residues applied to an organically managed cabbage field by favoring alternative prey may improve the suppression of lepidopteran pests by indigenous generalist predators. The trophic characteristics of predators were determined by a stable isotope approach (δ13C and δ15N). The relative contribution of alternative prey in predators species' (i.e. wolf spiders) diet was estimated using a mixed model based on their stable isotope signatures. As expected, densities of alternative prey became significantly higher in the plots with added plant residues. Consequently, population densities of predators (wolf spiders, predacious carabids and Japanese tree frogs) also became relatively higher and pest densities lower in these plots. We also note that, besides lepidopteran pests, alternative prey accounted for approximately 80% of predator diets. This finding suggests that they may play an important role in population persistence of generalist predators. The application of organic matter to the field for the enhancement of natural enemies’ impacts through increased alternative preys, which might be useful to manage lepidopteran pests in organic cultivation of cabbage.