Natural Pest Control Research Articles

The impact of insecticides on beneficial arthropods in cotton agro-ecosystems in South Africa.

The unique diversity of beneficial arthropods in South Africa can be regarded as an important natural resource in agro-ecosystems as it plays an important role in the natural control of insect pests. Insecticide applications reduce the ability of these beneficials to regulate cotton pests. In the absence of insecticides, average daily predation rates of 37% and 30% of bollworm eggs and larvae respectively were found in exclusion experiments. By minimizing the number of pesticide applications the combination of the direct negative effect of pesticide application on predator populations and secondary pesticide effects such as the stimulation of red spider mite populations as a result of predator suppression, can be avoided. This would open the option to fully utilize the full pest control potential of the natural enemy complex.

Modified summer programme using border sprays for managing codling moth, Cydia pomonella (L.) and apple maggot, Rhagoletis pomonella (Walsh) in Ontario apple orchards

The efficacy of two insecticide control programmes for managing codling moth, Cydia pomonella, and apple maggot, Rhagoletis pomonella, were compared in commercial apple orchards in Norfolk County, Ontario, Canada, during the 1993 and 1994 growing seasons. In the cover spray programme, sprays of organophosphorous (OP) insecticide for codling moth and apple maggot control were applied to the entire orchard following Ontario integrated pest management guidelines for apple. In the border spray programme, an initial cover spray of OP insecticide was applied to the entire orchard to eradicate any codling moths that had colonized the orchard during the previous growing season, and subsequent sprays were applied only to a c. four-tree-wide (i.e. c. 20 m) zone around the perimeter of the orchard. The border sprays were applied to control codling moths or apple maggots that invaded the orchard since application of the initial cover spray. The border spray programme provided control of codling moth and apple maggot similar to that obtained using the cover spray programme with no significant increase in other pest damage. One benefit of using the border spray programme would be a reduction in the cost of controlling codling moth and apple maggot. Another benefit of using this programme might be an increase in the natural control of other orchard pests like leafminers, aphids and mites. A border spray programme should only be used in orchards where codling moth and apple maggot have previously been reduced to non-detecfable levels and border sprays should be replaced with cover sprays when fruit infested with either of these pests is detected during routine monitoring in the orchard.

Traditional knowledge and rationale for weaver ant husbandry in the Mekong delta of Vietnam

The weaver ant, Oecophylla smaragdina Fabricius (Hymenoptera: Formicidae), has long been known as perhaps the first example of human manipulation of a natural predator population to enhance the natural biological control of insect pests. The practice of ant husbandry in Vietnamese citrus orchards and the knowledge associated with the use of weaver ants in the Mekong delta are described. In contrast to other regions of Asia, where weaver ants are noted for their role in the protection of citrus from insect damage, citrus farmers in the Mekong delta explain the benefits of ant husbandry in terms of an improvement in fruit quality, likened to the influence of fertilizers, that occurs in direct response to excretory products deposited by the weaver ants as they patrol the fruit. A series of tests, carried out in 1993–94, rated the external shine, sweetness, juiciness, and overall appeal, as characteristics of fruit quality, for paired comparisons of sweet orange, mandarin, and pummelo fruit that had been grown in the presence of weaver ants or from which ants had been excluded. The tests indicate a strong influence of the presence of the weaver ant on external shine, juiciness, and overall appeal for each of the citrus fruits, but particularly for mandarin. The significance of these results and ant husbandry practices in the Mekong delta are discussed in relation to the development of citrus production in Vietnam.

How Spiders Make a Living

Although the beneficial status of the spiders as insectivores has been widely recognized for quite some time, biologists by and large seem to be rather unfamiliar with the specific feeding habits of this very diverse order. We present an overview of the feeding patterns of 10 groups of common agroecosystem spiders to inform entomologists and ecologists concerned with issues of natural biological control. The various spider groups discussed in this article exhibit a very diverse range of life styles and foraging modes, which is reflected in the diversity of their feeding patterns. Implications of the insectivorous activities of these predators for natural pest control are discussed.

Science and people: Honduran campesinos and natural pest control inventions

Farmers are experts on their natural environment and are innate experimenters. However they do not know everything. Filling in gaps of missing farmer knowledge can help them improve their experiments. The authors designed and taught a course to Honduran farmers that effectively covered a number of key points on insect ecology and biology that farmers had not understood. After receiving the course many farmers did experiments to solve pest problems without synthetic pesticides.

ANTIFEEDANT AND GROWTH INHIBITORY EFFECTS OF TALL OIL AND DERIVATIVES AGAINST THE VARIEGATED CUTWORM, PERIDROMA SAUCIA HÜBNER (LEPIDOPTERA: NOCTUIDAE)

AbstractCrude tall oil and two of its derivatives were assessed for antifeedant and growth inhibitory effects, via incorporation into an artificial diet, in the variegated cutworm (Peridroma saucia Hübner). The substances tested are both toxic to neonate P. saucia and inhibitory to larval growth. The dietary LC50 (lethal concentration for 50% mortality) values are 4.3, 4.7, and 5.3% fresh weight for depitched tall oil (DTO), crude tall oil (CTO), and tall oil pitch (TOP), respectively. These materials significantly reduced growth, feeding, and dietary utilization by first-, second-, third-, and fourth-instar larvae in chronic larval growth bioassays, choice and no-choice feeding tests, and nutritional experiments. The EC50s (effective concentration to inhibit growth by 50% relative to controls) of DTO, CTO, and TOP were 1.4, 2.0, and ≥2.4%, respectively, when first-instar larvae fed on treated diets for 10 days. DTO significantly reduced both growth and consumption rates with corresponding reduction in the efficiency of conversion of food (i.e. nutritional efficiency), suggesting that both antifeedant and toxic effects are involved in larval growth inhibition. DTO and CTO are consistently more biologically active than TOP. Our results suggest that an environmentally sound, low cost natural pest control agent may be developed based on tall oil.

Prospects for the development of a genetically engineered baculovirus insecticide

Baculoviruses are insect-specific pathogens which have been employed for the natural control of insect pests for many years. They present an alternative to the use of chemical agents for crop protection. Their restricted host range enables particular pest species to be targeted, and this prevents any loss of beneficial insects from a treated area. However, their large-scale development as insect control agents has been limited because they take longer to kill the host following infection than rapidly-acting chemical insecticides. The aim of genetic modification of baculoviruses is to increase their speed of action, while preserving their beneficial characteristics, so creating a fast-acting, environmentally friendly insecticide. The prospects for achieving this are discussed in this paper, with consideration of scientific progress and the influence of economic and legislative factors.

Agricultural production systems and environmental health.

By the turn of the century, American farmers and ranchers will be producing food and fiber through the application of highly sophisticated systems that involve a broad spectrum of relevant factors--from soil type, to options for fertilizer and pesticide use, to markets and other economic information. These systems will help farmers and ranchers better match land use to land capability, apply needed conservation practices, make environmentally sound production choices, and lower production costs. Most importantly, they will aid in selecting the best combinations of chemical and the biological means for producing and protecting plants and animals. The systems will also help complement currently available and new classes of chemicals with biological control mechanisms such as natural predators and naturally occurring protective phenomena such as allelopathy and other forms of resistance to insects, weeds, and disease. Additionally, they will incorporate the use of biodegradable, slow-release, or timed-release natural and synthetic pest control materials. Also, scientists will increasingly emphasize nutrition and food safety in the development of plant and animal germplasm and production and processing methods.

Agricultural Production in the Third World - a Challenge for Natural Pest Control

SUMMARYPrevention of the enormous losses of crop production in the Third World, both before and after harvest, would make a substantial contribution to the survival and well-being of countless small fanners. Many attempts to reduce the scale of pest attacks by facilitating the purchase of pesticides and fertilizers have failed in the face of maladministration, mistrust, primitive conditions and ignorance. Yet, despite the difficulties, these fanners have evolved a pattern and practice of production which incorporates many positive attributes which have only recently been appreciated by western scientists. Attention is drawn to some of these methods and also to the benefits and limitations of both classical and manipulated biological control. It is concluded that further improvements depend on the ability of entomologists to adapt some of the concepts widely used in China to utilize scientific techniques within a socio-economic structure where even the plastic bag must be regarded as high technology.

Spiders in natural pest control: A review1

AbstractIn spite of the large number of studies about the ecology of spiders carried out in the last two decades in different types of ecosystems all over the world, the significance of these animals as natural control agents is still largely unknown. In this paper the literature about that subject is reviewed. Totally 300 scientific papers, published between 1920 and 1984, are cited here.Several European and American studies have provided evidence, that in undisturbed grassland ecosystems and forest ecosystems spiders can play an important ecological role as predators of insects and other invertebrates. Also in orchards, not treated with pesticides, that are to a certain degree comparable with forest ecosystems, spiders can be abundant predators.In contrast to that, the opinion about the predatory importance of spiders inhabiting cultivated fields is controversial. The results of some European studies indicate, that the foliage‐dwelling spiders of cultivated fields, because of their low population densities, are of minor importance as predators of insects. Other European studies show, that the ground‐dwelling spiders of cultivated fields are concerning their abundance a dominant predator group, those significance as control agents still is largely unknown up to the present. In rice fields (swamp ecosystems) in Asia, receiving little or no pesticides, as well as in European and American swamp ecosystems, spiders may be an important predator group.In houses in South Africa spiders were used successfully as biological control agents against flies.ZusammenfassungSpinnen in der natürlichen und biologischen Schädlingsbekämpfung: Ein LiteraturüberblickWeltweit wurden in den letzten 20 Jahren in verschiedenen Ökosystem‐Typen zahlreiche Studien über die ökologische Bedeutung der Spinnen als Prädatoren durchgeführt. Trotz der großen Zahl durchgeführter spinnenökologischer Studien ist die Funktion der Spinnen als Prädatoren von Insekten und anderen Invertebraten heute noch weitgehend ungeklärt. In vorliegender Arbeit wird die Literatur über dieses Thema (insgesamt sind 300 wissenschaftliche Arbeiten, die zwischen 1920 und 1984 über dieses Thema publiziert wurden, aufgeführt) analysiert.Mehrere europäische und amerikanische Studien haben gezeigt, daß Spinnen in unbewirtschafteten Grasland‐Ökosystemen und Forst‐Ökosystemen eine große ökologische Bedeutung als Prädatoren von Insekten haben können. Auch in ungespritzten Obstanlagen, die man bis zu einem gewissen Grad mit Forst‐Ökosystemen vergleichen kann, stellen Spinnen manchmal eine häufige Prädatorengruppe dar. Im Gegensatz dazu ist die ökologische Bedeutung der in Kulturfeldern lebenden Spinnen als Insektenvertilger noch weitgehend umstritten. Einige europäische Studien deuten darauf hin, daß den in der Vegetationsschicht von Kulturfeldern lebenden Spinnen ihrer niedrigen Populationsdichten wegen wahrscheinlich keine große Bedeutung als Prädatoren von Insekten zukommt. Aus anderen europäischen Studien geht hervor, daß die epigäischen Spinnen der Kulturfelder bezüglich ihrer Abundanz eine dominante Prädatorengruppe darstellen, deren Funktion als Kleinräuber allerdings noch weitgehend unbekannt ist. In asiatischen Reisfeldern, die nicht oder wenig mit Pestiziden behandelt wurden, können Spinnen eine wichtige Bedeutung als Prädatoren von Schädlingen haben. Reisfelder sind Sumpf Ökosysteme; auch in europäischen und amerikanischen Sumpfökosystemen können Spinnen eine abundante Prädatorengruppe darstellen.In Südafrika wurden Spinnen erfolgreich bei der biologischen Bekämpfung von Fliegen in Häusern eingesetzt.

ACTIVITY AND DISTRIBUTION OF CARABIDAE, ARACHNIDA, AND STAPHYLINIDAE IN NEW BRUNSWICK POTATO FIELDS

AbstractA 3-year faunal survey of insecticide-free potato fields revealed that Carabidae were the most abundant ground arthropods followed by Arachnida and Staphylinidae. Generic and species composition of Carabidae did not vary substantially from year to year but abundance did. The arthropods were distributed along a gradient decreasing with distance from the edge of the field closest to the woodland. Results of yellow pan trappings indicated that all types of Carabidae present in the pitfalls could fly but that flight activity was variable among genera. More than 50% of Staphylinidae and 85% of the Carabidae were trapped in the yellow pans at the time of field colonization in June. The significance of these findings in relation to the potential of the arthropods for natural biological control of potato pests is discussed.

THE EFFECT OF COMPANIONATE PLANTING ON LEPIDOPTERAN PESTS OF CABBAGE

Companionate planting is one of many insect control strategies propounded by organic growers. A variety of herbs are purported to possess repellent properties to many insect pests of vegetables (Rodale 1975; Yepsen 1976; Hill 1976; Anonymous 1977a). According to Atsatt and O'Dowd (1976), repellent plants are members of plant defense guilds which prevent herbivores from locating their hosts. Perrin and Phillips (1978) reviewed the elements of natural pest control characteristic of mixed cropping systems and outlined suggestions for transferring these elements to “agronomically acceptable” monocultures. However, very little work has been done to substantiate these claims and field evidence of the protective properties of companionate plants is, therefore, warranted. This becomes all the more important because of the dramatic increase in home gardening recently in North America. It is estimated that 33 million home and community gardens were grown in the United States during 1976 and 1977 (Anonymous 1977b). Here we describe the results of field experiments in which we sought to quantify the effect of companionate plants against major lepidopteran pests of cabbage in southside Virginia.

Progress towards the integrated control of sugar cane pests

AbstractSugar cane is an important tropical and sub‐tropical crop that occupies large areas of land around sugar factories capable of processing 5000 to 15 000 tonnes of cane per day. These areas are usually kept continuously under the same crop, about one‐tenth to one‐third of the land being ploughed and replanted with sugar cane every year. The major pests of sugar cane are rats, stalk borers, white grubs and froghoppers. Other important pests include root‐feeding nematodes, top borers, scale insects, planthoppers and soldier fly. Chemical control is practised to some extent against most of these pests, although biological control is the most common method of combating stalk‐borers and has had other notable successes, particularly in Hawaii and Mauritius. Rats are controlled with baits incorporating poisons such as anticoagulants, endrin or zinc phosphide. Aerial applications of insecticide sprays, dusts or granules are used against some stalk‐borers (azinphos‐methyl), froghoppers (omethoate, propoxur, vamidothion, methidathion, monocrotophos, malathion, carbaryl, gamma‐HCH) and plant hoppers (malathion, fenitrothion, endrin). White grubs, soldier fly (crude HCH, dieldrin) and nematodes [1,2‐dibromoethane (EDB), 1,2‐dibromo‐3‐chloropropane (DBCP), aldicarb] are usually controlled with soil applications of the appropriate chemicals. The use of chemical control is restricted in some areas because it is too costly and in other areas because of its possibly adverse effects upon the natural or biological control of other pests. Historically, pest control in sugar cane has tended to develop towards a simple integrated system, making use of cultural methods in conjunction with chemicals or exotic parasites and predators. Increasingly, allowance has been made for the contribution of indigenous natural enemies to the prevention of crop losses by a more careful, selective use of insecticides.

Biological control in temporary agroecosystems

The attributes of both natural enemies and pest species in temporary agroecosystems are discussed. Analysis of natural biological control of noctuid pests in California cotton provides empirical support for the view that certain natural enemies are well adapted to habitats of low durational stability and that such enemies are fully capable of effecting pest suppression in these habitats.

The relative injuriousness of insect pests of cotton in the Namoi Valley, New South Wales

Abstract The sequence and relative injuriousness of insect pests was studied for three successive years in unsprayed cotton of the Namoi Valley. Heliothis punctigera Wallengren, the native budworm, and to a lesser extent H. armigera (Hübner), the cotton bollworm, prevented the setting of full crops by destroying buds and bolls. After setting, high proportions of bolls were injured by Earias huegeli Rogenhofer, the rough bollworm. Incidental damage was caused to seedlings by Thrips imaginis Bagnall, the plague thrips, and lo leaves by Anomis flava Fabricius, the cotton looper, and by Austracris guttulosa (Walker), the spur‐throated locust. In commercial crops, pest control must rely on the use of broad‐spectrum insecticides: H. armigera is currently resistant to several of these, and has become the principal species in the local population of cotton pests.A number of enviromental features impede the natural control of pests in the southerly areas where cotton is now produced. In comparison to the older dryland cropping practised in central Queensland, a higher yield is necessary to cover the production costs of irrigated cotton; a shorter growing season prevents the plants from compensating effectively for insect damage and the natural enemies of cotton pests are less abundant and less active.

Effect of Strip-Planting vs. Solid-Planting on Predators of Cotton Insects in Southeastern Missouri, 1969 1 , 2

Natural control of cotton insect pests was high throughout the season in tests in two 20-acre fields, ½ of each planted to solid cotton and the other to 50-ft strips of cotton, alfalfa, corn, oats, and soybeans. Heliothis spp. damaged 1.06% of the bolls in solidplanted cotton and 0.60% of the bolls in strip-planted cotton in 1 field, but there was no difference in the 2nd field. Damage was below the economic threshold in all plots. Predation of marked cabbage looper eggs was higher in strip-planted plots on the few dates when differences were significant. Average seasonal survival of marked eggs of cabbage looper, Trichoplusia ni (Hubner), for 72 hr was 35.4% less in the stripplanted plot in one field and 14.6% less in the strip-planted plot in the other field than in solid-planted plots. Populations of predators, primarily Orius insidiosus (Say) and coccinellids, generally did not differ significantly between solid-planted and stripplanted plots.

The Influence of Spray Programs on the Fauna of Apple Orchards in Nova Scotia. XIII. Effects of Perthane on Predators

In Nova Scotia, a spray program that integrates chemical and natural control of apple pests has been evolved which is both economical and satisfactory. Among the natural enemies of injurious arthropods that have been favoured by this program are a number of general predators. Further investigation of the ecological principles on which integration is based requires a more intensive knowledge of the factors that influence the densities of these predators. Because of the difficulties of investigating these factors in the orchard, methods of simplifying the predator-prey systems have been sought (Lord, 1956, 1962). These attempts assessed the effects of low dosages of DDT on the interrelationships of phytophagous mites and their natural enemies.

Chemical and Natural Control of Pests

Chemical and Natural Control of Pests

Chemical and natural control of pests

Chemical and natural control of pests

The Influence of Spray Programs on the Fauna of Apple Orchards in Nova Scotia. IX. Studies on Means of Altering Predator Populations

It has been established that a complex of predacious arthropods on apple trees in Nova Scotia can control phytophagous mite populations (Lord, 1949). Some of the predators, when sufficiently numerous, may also be important in the control of other pests such as the eye-spotted bud-moth, Spilonota ocellana (D. & S.), and the codling moth, Carpocapsa pomonella (L.). When predation has reduced the mite population to small numbers, the insect predators almost disappear from the orchard. In most orchards in this province, the use of spray materials innocuous to predators has greatly reduced the phytophagous mite populations. The low mite population is an important gain but it is not known whether the attendant small numbers of predators is advantageous in the natural control of pests in general. This will be answered in time by the experience of the growers and, meanwhile, further research is needed on the interrelations of the phytophagous and predacious species and on how they are affected by orchard practices and other factors. This involves studies on the food preferences and behaviour of many species. In addition, means must be found to modify cultural practices to make conditions as favourable as possible for certain species of predators.