EFFECTS OF PRECIPITATION ON CROP INSECTS

1970 ◽  
Vol 102 (11) ◽  
pp. 1360-1373 ◽  
Author(s):  
Bryan P. Beirne

Abstract A review and analysis of the literature showed that precipitation, or its absence, can regulate the numbers of or the damage by insect pests of annual crops in Canada in essentially four main ways: as soil moisture, when the insects are in the ground; as a mechanical factor that impinges directly on them when they are exposed; through its effects on foodplants; and through its effects on natural enemies of the pests. Though any one pest species may be influenced by two or more of these processes and in different ways by each depending on the stage of its life cycle that is affected, usually only one way is significant. Precipitation is so far of little value in forecasting pest situations reliably, but water in various forms has much potential for use as a pest control agent.

1996 ◽  
Vol 14 (1) ◽  
pp. 22-26 ◽  
Author(s):  
D. Casey Sclar ◽  
Whitney S. Cranshaw

Abstract Use of systemic insecticides that can be injected either into the root system or trunk of woody plants provides several potential advantages, notably in control of drift during application. Recently, new classes of insecticides with systemic activity have been developed, which may supplant the organophosphate and carbamate systemic insecticides that have previously been available. To evaluate their potential to control insects affecting shade trees, studies were conducted using imidacloprid and abamectin on elm. Soil injections of imidacloprid appeared particularly effective, controlling all three of the target pest species in this study (elm leaf beetle, European elm scale, elm leaf aphid). Both imidacloprid and abamectin also were effective against at least some elm insects when injected into trunks. Persistence of irnidacloprid was unusually long, providing second season control of all elm insect pests, although root uptake following soil injections was slow.


1988 ◽  
Vol 3 (2-3) ◽  
pp. 102-109 ◽  
Author(s):  
Joop C. van Lenteren

AbstractThe number of species of insect pests, estimated to be maximally 10,000 worldwide, forms only a small part of the millions of species of plant-eating insects. Chemical pest control is becoming increasingly difficult and objectionable in terms of environmental contamination so that other methods of pest control need to be developed. One of the best alternatives is biological control. Natural and inoculative biological control has already proven successful against a variety of pests over large areas. One is inclined to forget, however, how successful a biological control program has been as soon as the pest problem has been solved. Other types of biological control involving the regular introduction or augmentation of natural enemies are better known, although these have been applied on a much smaller scale; a survey of the present-day application of these latter types of biological control is presented here. Phases in the implementation of biological control are illustrated and needed future developments in research are discussed. The main limitation on the development of biological control is not the research, since natural enemies are easier found and with a much lower investment than new chemical pesticides, but rather the attitudes held by growers and disinterest on the part of industry, policy-makers, and politicians. The first priority for those concerned with the development and application of safer pest control should, therefore, be to change the perceptions that these other groups have of biological control.


Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 326
Author(s):  
Liu Zhang ◽  
Zifang Qin ◽  
Pingping Liu ◽  
Yue Yin ◽  
Gary W. Felton ◽  
...  

Natural enemies play an important role in managing insect pests. Orius sauteri (Poppius) (Hemiptera: Anthocoridae), a predator of many soft-body insects, is an important biological control agent in Asia. Understanding this predator’s egg-laying preferences and a habitat needs is important for its success in pest control. We investigated the plant acceptability and ovipositional preference of O. sauteri for coriander (Coriadrum sativum L., Apiales: Apiaceae), marigold (Tagetes erecta L., Asterales: Asteraceae), sweet alyssum (Lobularia maritima L., Brassicales: Brassicaceae), and alfalfa (Medicago sativa L., Fabales: Fabaceae), and focused on the effects of plant physical and anatomical characteristics on the ovipositional preference of O. sauteri. The results showed that O. sauteri can lay eggs on uninfested plants in the vegetative stage and their eggs hatched normally. Orius sauteri females prefer plants with high stomatal density, a large stomatal area, and fewer trichomes as oviposition hosts, and the depth of egg placement was determined by leaf thickness. Our studies suggested that O. sauteri females can select oviposition hosts and specific oviposition sites by assessing the structural qualities of plant surface. Coriander and marigold are potentially suitable host plants for O.sauteri. The results aid the selection of cover crops to enhance natural enemies in the fields.


Author(s):  
Joakim Pålsson ◽  
Mario Porcel ◽  
Teun Dekker ◽  
Marco Tasin

AbstractThe widespread use of pesticides along with the simplification of the landscape has had undesirable effects on agroecosystems, such as the loss of biodiversity and the associated ecosystem service biological control. How current production systems can be remodelled to allow for a re-establishment of biological pest control, while preserving productivity, is a major challenge. Here, we tested whether a combination of tools could augment or synergize biological control of insect pests in apple (Malus domestica), comprised of a tortricid pest complex, a geometrid pest complex and the rosy apple aphid. The tools aimed at disrupting mating behaviour of multiple pest species (multispecies mating disruption, “Disrupt”, MMD), attracting natural enemies (a blend of herbivory-induced volatiles, “Attract”, A), or providing refuge and rewards for a diverse insect community (perennial flower strip, “Reward”, R) over a 3-year period. Suction samples were consistently richer in generalist predators but not in parasitoids when multiple tools including MMD + A + R or MMD + A were employed. In addition, lepidopteran pest levels were significantly lower in these plots than in MMD or MMD + R at the end of the 3-year experiment. This was, however, not reflected in survival of artificially established aphid colonies. Our data indicates that multiple, complementary tools can greatly enhance natural enemy level, but also that long-term implementation is needed to fully realize the augmentatory or synergistic potential of complementary components and restore biological control as an ecosystem service of practical relevance.


2019 ◽  
Vol 30 (6) ◽  
pp. 250-253
Author(s):  
Adrianna Szczepaniec

Invasions of alien insect pests often result in dramatic shifts in the entire ecosystems brought about by severe outbreaks of the pests exploiting new and frequently defenseless host plants. The explosive population dynamics of invasive insects often enable them to outcompete native pest species and alter both the abundance and diversity of communities of their natural enemies. These impacts are probably the most conspicuous and notorious when the invaded host plant is a key commodity crop and the invasive pest an aphid (Hemiptera: Aphididae). Aphids have a remarkable ability to overwhelm their plant hosts extremely rapidly owing to their parthenogenetic reproduction (i.e., daughters are clones of their mothers), live birth, and telescoping generations (i.e., the offspring of unborn aphids are already developing within their bodies). Aphids also attract exceptionally diverse communities of predators and parasitoids, which are strongly attracted to the volatiles emitted from plants attacked by aphids, albeit the natural enemies' attraction to invasive aphids often requires a period of adaption to recognize a new prey. Hence, when new species of aphids invade a new agroecosystem, their presence frequently creates an ?ecosystem earthquake' that can have profound implications for long-term stability of the system most directly affected by the invasive aphid as well as neighboring crops.


2008 ◽  
Vol 48 (12) ◽  
pp. 1531 ◽  
Author(s):  
Joanne C. Holloway ◽  
Michael J. Furlong ◽  
Philip I. Bowden

Beneficial invertebrates (predators and parasitoids) can make significant contributions to the suppression of insect pest populations in many cropping systems. In Australia, natural enemies are incorporated into integrated pest management programs in cotton and horticultural agroecosystems. They are also often key components of effective programs for the management of insect pests of grain crops in other parts of the world. However, few studies have examined the contribution of endemic natural enemies to insect pest suppression in the diverse grain agroecosystems of Australia. The potential of these organisms is assessed by reviewing the role that natural enemies play in the suppression of the major pests of Australian grain crops when they occur in overseas grain systems or other local agroecosystems. The principal methods by which the efficacy of biological control agents may be enhanced are examined and possible methods to determine the impact of natural enemies on key insect pest species are described. The financial and environmental benefits of practices that encourage the establishment and improve the efficacy of natural enemies are considered and the constraints to adoption of these practices by the Australian grains industry are discussed.


2016 ◽  
Vol 4 (1) ◽  
pp. 71-80
Author(s):  
A Awal ◽  
MM Rahman ◽  
MZ Alam ◽  
MMH Khan

Experiment was conducted during winter season to study the diversity and equitability of insect pest species and natural enemies in insecticide treated brinjal fields. Highest number of insect pests were recorded in` Tracer 45 SC, Bactoil (Bt), Nimbicidene 0.03 EC and lowest was in Necstar-50 EC and Proclaim-5 SG treated plots. The highest total abundance of insect pest was recorded in the plots treated with Bactoil and Tracer-45 SC and lowest total abundance was in Helicide (HNPV), Proclaim-5 SG and Booster-10 EC treated plots. The diversity index and equitability of insect pest species were highest in the plots treated with Nimbicidene 0.03 EC and Bactoil in visual search and sweep net methods while Bactoil and Booster 10 EC in pitfall trap method. However, lowest diversity index and equitability were obtained from the plots treated with Booster 10 EC, Proclaim-5 SG, Necstar-50 EC, Tracer-45 SC in visual search and sweep net methods but also in plots treated with Nimbicidene 0.03 EC in pitfall trap method. In case of natural enemies, the highest number of families were recorded in Tracer-45 SC, Nimbicidine 0.03 EC and Bactoil treated plots while lowest was in Helicide, Booster 10 EC, Proclaim-5 SG and Necstar-50 EC treated plots. The highest total abundance of natural enemy was recorded in the plot treated with Bactoil and Tracer-45 SC while lowest abundance was in the plot treated with Necstar-50 EC and Boster-10 EC. The diversity index and equitability of natural enemies were the highest in the plots treated with Proclaim-5 SG, Bactoil, Helicide and Necstar-50 EC in visual search, sweep net method and pitfall trap method while lowest was in Booster 10 EC, Tracer-45 SC treated plots in visual search method, Booster 10 EC and Nimbicidene 0.03 EC treated plots in sweep net method, Necstar-50 EC and Nimbicidene 0.03 EC treated plots in pitfall trap method. Bactoil and Tracer-45 SC were relatively safe for natural enemies and therefore would be fit well into integrated pest management (IPM) against BSFB of brinjal crop.Jahangirnagar University J. Biol. Sci. 4(1): 71-80, 2015 (June)


2019 ◽  
Vol 11 (22) ◽  
pp. 6399 ◽  
Author(s):  
Prisila A. Mkenda ◽  
Patrick A. Ndakidemi ◽  
Philip C. Stevenson ◽  
Sarah E. J. Arnold ◽  
Steven R. Belmain ◽  
...  

Non-crop vegetation around farmland can be valuable habitats for enhancing ecosystem services but little is known of the importance of field margins in supporting natural enemies of insect pests in tropical agriculture. This study was conducted in smallholder bean fields in three elevation zones to assess the importance of field margin vegetation to natural enemy populations and movement to the bean crop for biological pest control. The pests and natural enemies were assessed using different coloured water pan traps (to ensure the capture of insects with different colour preferences) and the interactions of the two arthropod groups with the margin vegetation and their movement to the bean crop were monitored using fluorescent dye. Sentinel plants were used to assess predation and parasitism levels. A total of 5003 natural enemies were captured, more in the field margin than within the bean field for low and mid elevation zones, while in the high elevation zone, they were more abundant within the bean field. Pests were more abundant in the crop than margins for all the elevation zones. The use of a dye applied to margin vegetation demonstrated that common natural enemy taxa moved to the crop during the days after dye application. The proportion of dye-marked natural enemies (showing their origin to be margin vegetation) sampled from the crop suggest high levels of spatial flux in the arthropod assemblage. Aphid mortality rates (measured by prey removal and parasitism levels on sentinel plants) did not differ between the field edges and field centre in any of the three elevation zones, suggesting that for this pest taxon, the centre of the fields still receive comparable pest control service as in the field edges. This study found that field margins around smallholder bean fields are useful habitats to large numbers of natural enemy taxa that move to adjacent crops providing biological pest control service.


2021 ◽  
Vol 2 (2) ◽  
pp. 121-125
Author(s):  
Erniwati Erniwati ◽  
◽  
Tiara Sayusti ◽  
Woro Anggraitoningsih Noerdjito ◽  
◽  
...  

Plectranthus rotundifolius is an edible tuber that widely distributed in Asia, covers India, Sri Lanka, Malaysia, and Indonesia. Plectranthus rotundifolius which commonly called as black potato in Indonesia is potential to be developed for national food diversification due to its high carbohydrates. However, one of challenges in black potato culture is the existence of moth pest infected the plants. This study was aimed to evaluate the status of Paliga auratalis moth as an insect pest in black potato plant and to develop the countermeasure strategy through its natural enemies. Observation and collection of P. auratalis and other potential insect pests was conducted in 12 black potato plantations located in five provinces of Java Island. The life cycle of P. auratalis was observed in the laboratory of Zoology Division, Research Center for Biology, Indonesian Institute of Science. Rearing of unhealthy P. auratalis larvae was also conducted to observe its natural enemies. We identified five species of moths infested black potato plants i.e.: Argyrograma sp., Pycnarmon cribat, Pleuroptya punctimarginalis, Rehimena diemenalis, and Paliga auratalis. Based on our observation, we confirmed that. P. auratalis is the main insect pest in Java Island with serious stack status. P. auratalis spend its lifecycle from eggs to adult between 25 – 32 days with the total eggs about 60-80 per female individual. We also identified two parasitic wasps as the natural enemies of P.auratalis i.e.: Aspanteles sp. and Cryptopimpla sp. which are potential to be a biological control agents of P. auratalis.


2021 ◽  
Author(s):  
Xu Chen ◽  
Coline C. Jaworski ◽  
Huijie Dai ◽  
Yuyong Liang ◽  
Xiaojun Guo ◽  
...  

Abstract Banker plants increase biological pest control by supporting populations of non-pest arthropod species used as alternative hosts or prey by natural enemies. Due to the specificity of trophic interactions, banker plants may not efficiently promote natural enemies with different ecologies. Yet in most cropping systems different pest species are present together and require different biocontrol agents to efficiently control them. In the present study, we tested the combined use of two banker plants and their associated prey / host to enhance populations of the specialist parasitoid Encarsia formosa targeting the main tomato pest Bemisia tabaci, and a polyphagous ladybird Propylea japonica targeting the secondary pest Myzus persicae in tomato crops. In a laboratory and a greenhouse experiment, we measured the abundances of these four species using the Ricinus communis – Trialeurodes ricini banker plant system alone, in combination with the Glycines max – Megoura japonica system, or in absence of banker plants. We found that the first banker plant system enhanced populations of E. formosa, resulting in higher control of B. tabaci populations and the suppression of their outbreak in both our laboratory and greenhouse experiment. Conversely, abundances of P. japonica were not affected by this first system, but were significantly increased when the second was present. This resulted in high control of M. persicae populations and the suppression of their early and late outbreaks. Our study demonstrates the potential for combined banker plants to provide long-term, sustainable control of multiple pests by their target natural enemies in complex agroecosystems.


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