The Biology and Control of the Grasshopper Zonocerus variegatus

Abstract

The grasshopper Zonocerus variegatus (L.) is recognised as a pest of many crops in West Africa. Evidence that it is becoming an increasing problem in southern Nigeria prompted research into the biology, bionomics and control of this insect. Summaries of the main points in the biology, bionomics and recommended control are given. It is concluded that although a chronic pest it only periodically causes economical damage to cassava and community self help is the best level at which to effect control.     

The Build-up of the Present Desert Locust Plague

Abstract

Imperata cylindrica is one of the most noxious weeds in South East Asia. Over the past two decades significant advances have been made in the understanding of its biology and control. This paper reviews work over this period and concludes that despite such advances, there remains much scope for improvement of control, particularly in development of methods appropriate for small scale farmers with limited resources.     

Distribution,biology, ecology and control of the psyllid Diaphorina citri Kuwayama,a major pest of citrus: A status report for China

Abstract

The Asiatic citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a major pest of citrus in China. Its status derives, not from the damage it causes, but from its role as the only known vector in China of huanglongbing, a phloem-limited bacterial disease of international importance. The disease can devastate orchards within a few years of planting. It also poses a major threat to endangered indigenous citrus germplasm in Asia and Australasia. The distribution, biology, ecology and control of the psyllid in China are reviewed in these contexts. Constraints and challenges related to control of the vector in China are discussed.     

Potential biological control agents for Mikania micrantha hbk from the Neotropical region

Abstract

Mikania micrantha HBK, a sprawling composite vine native to the Neotropics, is a serious weed of plantation crops in Southeast Asia. A survey and assessment of its natural enemies in the Neotropics reveals nine major natural enemies and over 20 minor ones. The biology of the nine major natural enemies: Acalitus sp. (Acarina, Eriophyiidae), Liothrips mikaniae (Priesner) (Thysanoptera, Phloeothripidae), Teleonemia sp. (Heteroptera, Tingidae), Desmogramma conjuncta Bechyné, Physimerus pygmaeus Jacoby, Omoplata spp. (Coleoptera, Chrysomelidae), Apion luteirostre Gerst. (Col., Apionidae), Pseudoderelomus baridiiformis Champ. (Col., Curculionidae), together with brief accounts of the minor ones, forms the bulk of this paper. The prospects for biological control of M. micrantha are considered reasonable, and an outline for a continuation of work on the project is given, beginning with the introduction of L. mikaniae to Southeast Asia.     

Bactra spp. in Pakistan and their Potential as Biocontrol Agents of Cyperus rotundus

Abstract

Observations on distribution, abundance, phenology, host spectrum, biology and damage of Bactra venosana and B. minima are reported. Morphological differences between larvae and pupae of the two species for field identification are given. Oviposition and larval feeding tests were carried out and showed that oviposition is indiscriminate but larvae have a strong preference for Cyperus rotundus though they also feed on some other Cyperus spp. In laboratory experiments 72% of plants damaged by B. venosana and 65% by B. minima failed to regenerate. The ecological preferences of B. venosana and B. minima are also discussed and as a result both species are recommended for simultaneous introduction for the control of C. rotundus in areas where other Cyperus spp. are not economically important.     

Improving Control of the Vegetable Armyworm

Abstract

Because of recently acquired resistance of armyworm in Cyprus to prophyllactic spraying of methylparathion, a full investigation into the biology of Spodoptera littoralis was launched. It is not yet clear whether immigration to the Island occurs, but some moths can overwinter in “survival pockets” on the South coast. Pheromone traps and sterilisation are suggested as an alternative method of control. A more rational use of pesticides will cause less damage to natural enemies of the pest and reduce further development of resistance.     

Insect Pests of Soyabean in Japan and their Control

Abstract

From thirty species of economic importance, the biology, damage caused and control measures for three pod borers, one pod gallmidge and four stink bugs are reviewed. Some high correlations have been recognised between the percentage of injured seed at harvest time and the mean temperatures of January, July or August, and some equations have been obtained for forecasting the percentage of the damage to soyabean seeds. The late podding varieties are generally less damaged by major pests. Even in one variety, damage decreased when sowing was delayed. Hence consideration should be given to the choice of variety and sowing date in order to avoid the coincidence of the peak of pest occurrence with the podding period of the soyabean plants. In the central southern region of the Tohoku district where all species of economic importance occur, insecticidal applications should be carried out when indicated by the forecast, two or three times at intervals of one to two weeks, during early pod-setting and on to the middle seed-thickening stage, using such insecticides as: fenthion, cyanophos, fenitrothion, phenthoate, acephate, chlorpyrifos or EPN.     

Cucurbit downy mildew (<Emphasis Type="Italic">Pseudoperonospora cubensis</Emphasis>)—biology,ecology, epidemiology,host-pathogen interaction and control

Cucurbit downy mildew, caused by the oomycete Pseudoperonospora cubensis, is a devastating, worldwide-distributed disease of cucurbit crops in the open field and under cover. This review provides recent data on the taxonomy, biology, ecology, host range, geographic distribution and epidemiology of P. cubensis. Special attention is given to host-pathogen interactions between P. cubensis and its economically-important cucurbit hosts (Cucumis sativus, C. melo, Cucurbita pepo, C. maxima, and Citrullus lanatus); pathogenic variability in P. cubensis at the species, genus, and population levels; and, differentiation of pathotypes and races. Genetics and variability of host resistance and cellular and molecular aspects of such resistance are considered. A focus is given to methods of crop protection, including prevention and agrotechnical aspects, breeding for resistance—classical and transgenic approaches, chemical control and fungicide resistance. Novel technologies in biological and integrated control are also discussed. This review also summarizes the most important topics for future research and international collaboration.     

Warning system in Portugal – organization and technical basis of forecasting*

The forecasting and warning system in Portugal started in 1964 with a control programme applied against Plasmopara viticola, the most important pathogen of grapevine. Since then, studies and new techniques have been developed and applied to other important pests of vineyards and orchards, on the basis of epidemiological and climatic data that supports technical evaluation of the risk. In the last few years, mathematical models have been evaluated as an important part of the control strategy, integrated with biological data from field monitoring. At the moment, forecasting models are available for Plasmopara viticola, Venturia pirina, Venturia inaequalis and Cydia pomonella. The integration of forecasting models with field observations is used to formulate warnings that are sent out to farmers about the need to spray or not.     

Athesapeuta cyperi in Pakistan and its Potential as a Biocontrol Agent of Cyperus rotundus

Abstract

The distribution, hosts, phenology and abundance of Athesapeuta cyperi, an insect enemy of purple nutgrass, Cyperus rotundus, in Pakistan are given. Its biology and damage to C. rotundus in the laboratory are also reported. Usually one egg was laid in a tuber. When two eggs were present, only one reached maturity. The infested tuber was completely hollowed out and failed to regenerate. Thus, 100% plants infested with A. cyperi were killed. In host specificity tests larval development occurred on Cyperus spp. and Fimbristylis ferruginea but oviposition was restricted to Cyperus spp. However, C. rotundus was preferred to other species of Cyperus both for oviposition and development.     

Insect pests of pearl millet in West Africa: A review

Abstract

Pearl millet (Pennisetum americanum (L.) K. Schum), a major food crop in the sahelian and savanna regions of West Africa, is attacked by about 100 species of insects. Of these, the only regular pests are stem borers (Acigona ignefusalis Hmps. and Sesamia spp.) and earhead caterpillars (Masalia spp., Raghuva spp.). Sporadic pests such as hairy caterpillars (Amsacta moloneyi Druce), armyworms (Spodoptera spp. and Mythimna spp.) and grasshoppers (Acrididae) may cause severe losses to crops during prolonged droughts early in the season. A grain midge (Geromyia penniseti (Felt)) attacks late millets and causes a considerable loss in yield. Information is presented on the biology, distribution, hosts and natural enemies of these pests, and some methods of control are discussed.     

Insect Pests and Mites

Abstract

Weeds are major components of agro-ecosystems and they affect the biology of pests and beneficial insects in several ways; provision of flowers, presence of neutral insects, modification of crop microclimate, production of chemical stimulus, alteration of colonisation background, etc. The more relevant beneficial crop–weed–insect interactions are discussed. The role of weeds in regulating pest populations is illustrated by studies on bean (Phaseolus vulgaris L.) cropping systems, in which chemical interactions between Empoasca kraemeri Ross &; Moore and two grass weeds were identified. It is proposed to continue and develop this kind of research in order to incorporate weeds into pest control strategies.     

An historical perspective of the ‘Blandford Fly’ (Simulium posticatum Meigen) problem and attempted control of the pest species using Bacillus thuringiensis var. israelensis

This review deals with the biology and control of a biting pest species, Simulium posticatum, which has been responsible for a considerable degree of distress to the human population in the vicinity of the River Stour in Dorset. Each phase of the life cycle of the insect is considered in relation to possible control measures. An account is given of how this information has been combined with the use of Bacillus thuringiensis in a successful, precisely targeted attack on the pest.     

Gastrophysa atrocyanae (Col: Chrysomelidae), an agent for biological control of the dock,Rumex japonicus (Polygonaceae) in China

Abstract

The biology and host specificity of the beetle, Gastrophysa atrocyanea Motch were studied in the laboratory in Nanchang, China. This univoltine insect completed its immature stage in 32–39 days with adult overwintering in soil. A total of 35 plant species from 21 families were tested. Both larvae and adults attacked Rumex japonicus and Rumex acetosa with R. japonicus the main host. Larvae also attacked two Polygonum species, P. hydropiper and P. perfoliatum. But the adults are not concurrent with the two Polygonum species. Though oviposition occurred on five other plant species, none of them supported larval development. Field observations showed that G. atrocyanae caused a progressive decline in natural R. japonicus populations. Thus it is recommended as a valuable biological agent for this weed.     

The European Weed Research Council's 3rd Symposium on Aquatic Weeds

Abstract

Parthenium has been recognised as a serious weed in Queensland only since 1974, but subsequently it has spread explosively mainly along roads in rangeland country. The weed has become the subject of an intensive research and control programme and large sums of Government money are being made available for its containment. The distribution and biology of this weed in Australia are described, and possible control measures discussed.     

Presence–absence sampling for Tetranychus urticae and its predator Neoseiulus californicus (Acari: Tetranychidae; Phytoseiidae) on strawberries

The use of snails as biocontrol agents against other snails and against aquatic weeds is reviewed, evaluating their success and their impacts on non-target organisms. The predatory snail Euglandina rosea (and other species), although widely used against Achatina fulica (the giant African land snail) on Pacific and Indian Ocean islands, has not been shown to control A. fulica but has seriously impacted endemic island species. The facultative predator Rumina decollata , used in California against Helix aspersa (brown garden snail), is widely considered to be environmentally benign. However, evidence of its effectiveness is weak and it will also consume native snails. Ampullariid and thiarid freshwater snails have been used as competitors (and incidental predators) of snail vectors of human schistosomes, the parasites causing schistosomiasis (bilharzia). Successful control has been reported but impacts on native biotas have been essentially ignored. Ampullariids have been used in attempts to control aquatic weeds, sometimes successfully, but again with little consideration of impacts on native biota. Most snails have generalist feeding habits. Thus they are inappropriate biocontrol agents because of their potential nontarget effects. Rarely has adequate pre-release testing of snails been undertaken and post-release monitoring of non-target impacts has always been incidental. The use of non-native snails for biocontrol purposes is poorly regulated; many introductions are unofficial and sometimes illegal. Use of snails as biocontrol agents, if implemented, must be based on adequate pre-release testing, post-release monitoring and genuine concern for preservation of native biodiversity.     

Coffee Rust in Latin America

Abstract

Nearly 500 samples taken from banana and over 30 other crops in the Windward Islands revealed the presence of 31 species of plant parasitic nematodes. The most common were: Radopholus similis, Helicotylenchus multicinctus, Rotylenchulus reniformis, Meloidogyne incognita, Tylenchulus semipenetrans and Xiphinema vulgare. A review of the plant parasitic nematodes recorded from the Windward Islands is given and the more important species are discussed. Details of banana nematode control are given.