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.     

Effect of plant nectars on adult longevity of the stinkbug parasitoid,Trissolcus basalis

Abstract

The egg parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae) is an important biological control agent of stinkbugs worldwide. Although honey has been used as adult food in culturing the parasitoid, no previous studies have explored the potential for maximising its fitness by provision of plant nectars in conservation biological control. In laboratory experiments, we measured the longevity of adult T. basalis females provided with each of 10 nectar-bearing flowering plant species: Lobularia maritima L., Brassica napus L., Tagetes patula L., Ocimum basilicum L., Fagopyrum esculentum Moench., Cosmos bipennatus Cav., Calendula arvensis L., Coriandrum sativum L., Tropaeolum majus L. and Phacelia tanacetifolia Bentham. Longevity was greatest (33 days) on flowering T. patula shoots and significantly lower on shoots of this species from which the inflorescence had been removed (8 days). Of the other plant species, only L. maritima flowers did not enhance longevity. These results indicate that adults of T. basalis benefit from access to floral nectar and also suggest plant species that merit field testing to identify species best suited to enhancing the efficacy of this parasitoid in conservation biological control.     

Epidemiology and Control of Greasy Spot,Melanose and Scab in Florida Citrus Groves

Abstract

Three major fungal diseases in Florida citrus groves that require control by chemical sprays are greasy spot (Mycosphaerella citri), melanose (Diaporthe citri) and scab (Elsinoe fawcettii). The salient features of pathogen behaviour and epidemiology are reviewed for each of these diseases. Timing of chemical sprays for optimum disease control is discussed in relation to local climatic conditions, seasonal bloom and shoot growth patterns and the mode of action of each spray material.     

Problem of flower shedding caused by thrips,Megalurothrips distalis (Karny), on summer mungbean,Vigna radiata (L.) Wilczek,and its control

Abstract

Flower shedding in summer mungbean, Vigna radiata (L.) Wilczek, is a common feature caused by thrips, Megalurothrips distalis (Karny). Eleven insecticides were tested in field trials for the control of thrips during the period 1982 to 1984. All the treatments were significantly better in controlling the thrips, reducing flower shedding, increasing the pod numbers and grain yield, in comparison with the control. Increases in yield compared with the control during trials ranged from 85 to 89% (1982), 26 to 96% (1983) and 5 to 194% (1984). Dimethoate gave the highest increases in yield and profit followed by monocrotophos and endosulfan.     

Attractants for Rhagoletis Batava Obseuriosa,a Fruit Fly Pest of Sea Buckthorn

Abstract

Sea buckthorn, Hippophae rhamnoides, is a widely distributed tree that contributes to soil and water conservation. Its fruit, seeds and leaves are also raw materials for many health products. Rhagoletis batava obseuriosa (RBO) is a fruit fly that attacks sea buckthorn berries; outbreaks have recently been reported on some large-berried cultivars of sea buckthorn in northern China. In order to develop tools to monitor and control of RBO, male lures and food-based attractants of other fruit fly species were evaluated with RBO. Results of the first field bioassays showed that ammonium acetate (AA) was a strong attractant for RBO adults. The subsequent results also showed a trend for ammonium bicarbonate (AB) and ammonium carbonate (AC) trapping an higher number of RBO adults than AA. Mixtures of AA and AC were no more attractive than AC used individually. Further research on attract and kill techniques using these ammonium-based compounds is now required.     

Effect of coffee pulp on Trichoderma spp. in Kenyan tea soils

Abstract

Six organic amendments and one soil sterilant (Basamid) were screened at different rates to a given amount of soil, for their efficiency to enhance the population of Trichoderma spp. Coffee pulp significantly (P = 0.01) enhanced the population of Trichoderma spp. in the soil compared to other amendments. The enhancement was rate‐dependent with 16 and 22 g carbon giving the optimum population. The Trichoderma species enhanced included T. koningii, T. harzianum and T. longibrachiatum. The implications of these results in relation to biological control of soil‐borne plant pathogens are discussed.     

Impact of Eucalyptus gall wasp,Leptocybe invasa infestation on growth and biomass production of Eucalyptus grandis and E. saligna seedlings in Tanzania

A study was carried out to determine the impact of Leptocybe invasa infestation on growth and biomass production of Eucalyptus grandis W. Hill ex Maiden and E. saligna Smith seedlings in Tanzania. Three- month old seedlings were infested with L. invasa. Twenty two weeks post infestation, heights of infested E. grandis seedlings were reduced by 39.6%, while diameters were reduced by 11.3% compared to uninfested seedlings. On the other hand, the heights of infested E. saligna seedlings were reduced by 38.2% and diameters were reduced 7.7% compared to uninfested seedlings. Dry weight biomass reduction of infested seedlings was significantly higher on stem and leaves than roots and branches of both E. grandis and E. saligna. The impact of L. invasa infestation on growth and biomass production was higher in E. grandis than E. saligna. Prevention and control of L. invasa infestation should be given priority. Similar future trials should examine other commercially grown Eucalyptus species in Tanzania.     

Ecology and Control of Erinnyis ello and E. alope,Important Insect Pests in the New World

Abstract

The sphingid moth Erinnyis ello L. is an important pest of cassava and the most serious pest of the rubber tree in the New World; E. alope Drury is sometimes a serious pest of papaya. Information on the known food plants, life cycle, behaviour, natural enemies, seasonal abundance and present methods of control of these two lepidopterous pests is reviewed. The perspectives for improved control of E. ello with special reference to rubber plantations in Brazil, through the manipulation of natural enemies, a more rational use of insecticides and the adoption of certain cultural methods, are discussed.     

Department of Crop Science,Herbicide Section,Report October 1967 - August 1968

Abstract

A serious outbreak of muskmelon (Cucumis melo L.) downy mildew caused by Pseudoperonospora cubensis (Berk. &; Curt) Rostow, occurred in the Punjab (India) due to unusual rain showers accompanied by high humidity. Nine different fungicides were evaluated and of these zineb 75% (Dithane Z-78) and copper oxychloride (Blitox 50%) gave reasonable control of the disease.     

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.     

Status of Pod Borers as Pests of Pigeon Pea in Uttar Pradesh,India

Abstract

The main pulse crop during the kharif season in Uttar Pradesh (India) is pigeon pea. Melanagromyza obtusa Malloch, Exelastis atomosa W., Heliothis armigera Hubn., Euchrysops cnejus Fab., Maruca testulalis Geyer and Anarsia ephippias Meyrick are the important pod borers which cause great damage to this pulse crop. The symptoms of attack and methods of pest control are described.     

Successful biological control of water hyacinth (Eichhornia Crassipes) by Neochetina eichhorniae (Coleoptera: curculionidae) in Bangalore,India

Abstract

Water hyacinth is the most serious aquatic weed in India, infesting more than 200000 ha of water surface. Successful biological control of this weed was achieved in a fully infested tank covering 20 ha at Bangalore. More than 95% of the infestation was cleared within 32 months by releases of Neochetina eichhorniae Warner. The insect also spread along a water channel and controlled water hyacinth infesting a nearby tank. Drying up of the tank after the insect population had spread throughout and increased to 3.1 adults/plant hastened weed control. Fresh plants emerging after rains were suppressed by the residual population of insects. N. eichhorniae along with N. bruchi Hustache is being supplied to centres throughout the country for multiplication and releases. Sustained efforts with these insects holds out promise of control of water hyacinth in India.     

Weed Control in Wheat and Barley in the Middle East

Abstract

Wheat and barley constitute the bulk of agricultural production in the Middle East. Unfortunately, these crops are grown on marginal soils which are infested with annual and perennial weeds. The principal weed species include Avena sterilis L., Convolvulus arvensis L., and Sinapis arvensis L. and it has been estimated that yield losses due to weeds are between 20 and 30%. Control is mostly by hand pulling, hoeing or mechanical tillage, the use of herbicides being limited to about 2–5%, of the cereal area. The chemical used is usually 2,4-D but there are a few applications of barban. With the increase in wages, and unavailability of agricultural labour it is suggested that herbicide application should be widely used in the Middle East. Mixtures with benzonitriles and dicamba should be used in addition to the economical phenoxy herbicides to widen the spectrum of control of broadleaved weeds. Glyphosate may also be used after grain harvest for the control of perennial weeds and tri-allate, chlortoluron and other chemicals for the control of wild oats and other grasses. Plant breeders should study the genetic response of newly developed varieties to the most widely used herbicides.     

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.     

Estimation of rice yield losses due to the African rice gall midge,Orseolia oryzivora Harris and Gagne

Abstract

The African rice gall midge, Orseolia oryzivora Harris and Gagne (Diptera: Cecidomyiidae), is an important pest of rice, Oryza sativa, in Burkina Faso as well as other countries in West and East Africa. In spite of its importance, little is known regarding the relationship between gall midge populations and grain yield losses. To determine yield losses the gall midge was reared in cages and adult midges were placed on caged plants of the rice variety ITA 123 at different population levels. The seven treatments consisted of different numbers of insects infested on the plants; 0 insect pairs (non‐infested check), and 1, 5, 10, 15, 20 or 25 midge pairs/cage. The loss in yield in relation to the non‐infested control was highly positively correlated (R² = 0.81) with the percentage of gall midge damaged tillers. The infestation by the insect on the plants resulted in the compensatory production of tillers which developed in response to the gall midge damage but the compensation was not sufficient to make up for the loss of yield due to the damaged tillers. Yield loss ranged from 0% in the control to 65.3% in the treatment with 25 pairs of adults. One per cent of tillers damaged resulted in 2% grain yield loss.     

Control of Schistosomiasis (Bilharziasis) in Brazil,Past, Present and Future

Abstract

Schistosoma mansoni was first recorded in Brazil in 1908, currently official estimates are that schistosomiasis is endemic in 1,000 municipalities and possibly ten million individuals are infected. Infection foci are rural communities and irrigated areas without sewage disposal facilities. In the past The Servicio Especial de Saúde Publica: The Servico Nacional de Malaria and later the Department of Rural Endemic Diseases (DNERu) attempted with some success to control the intermediate hosts, Biomphalarla spp., and improve sanitation and water supplies. Following examination of past policies DNERu in 1965 authorised the organisation of pilot projects for the control of schistosomiasis in 4 states: Pernambuco, Bahia, Minas Gerais, and Gaunabara. In 1970 the results of the pilot projects were evaluated and recommendations made regarding drug treatment and snail control for immediate use by the Superintendencia de Campanhas of the Federal Ministry of Health, involving the use of the drug Hycanthone, the molluscicide niclosamide (Bayluscide) and complimentary measures such as drainage and education in basic sanitation. In the future with the greater urbanisation of Brazil and increasing number of irrigation projects the incidence of the disease could increase. Improvements in sanitation, education and nutritional state will counteract this.     

Insect Enemies of Aquatic Weeds

Abstract

The Agricultural Research Service of the USDA has been actively engaged in research on the biological control of aquatic weeds since 1959. Research emphasis until 1967 was on alligatorweed, Alternanthera philoxeroides (Mart.) Griseb. As a result of this research, three species of insects from Argentina were released in the southeastern United States. Alligatorweed control with these natural enemies has been variable; but indications are that control will be substantial over most of the range of the weed.

One species of weevil, Neochetina eichhorniae Warner, has been released against water hyacinth, Eichhornia crassipes (Mart.) Solms, in the USA as a result of research in Argentina. A second closely related species, N. bruchi Hustache, is presently undergoing final clearance procedures. Several other arthropods are being studied in Argentina as possible biological control agents of water hyacinth.

A USA sponsored programme in Yugoslavia under the direction of Dr M Leki? resulted in the discovery of two insect species that show potential as control agents for eurasian watermilfoil, Myriophyllum spicatum L. Further testing for host specificity of these insects will be carried out in the USA in quarantine in Florida.

A USA sponsored Pakistan programme under Dr M. A. Ghani is investigating insects and other phytophagous organisms attacking Hydrilla verticillata Royle. The results are encouraging. PANS 20: 444–450, 1974.     

Recent Advances in the Use of Plant Pathogens as Biocontrol Agents of Weeds

Abstract

Among various organisms attacking skeleton weed, Chondrilla juncea, in Europe, a rust fungus, Puccinia chondrillina, and two powdery mildews, Erysiphe cichoracearum and Leveillula taurica f. sp. chondrillae were found to be the most damaging. P. chondrillina was shown to be specific to Chondrilla and has recently been introduced into Australia where skeleton weed is important in wheat cultivation. It has already spread throughout the weed infestations and is beginning to reduce plant populations. Encouraged by the result of the Chondrilla rust, the possible use of Puccinia xanthii for the control of Xanthium strumarium and X. spinosum has also been studied. Current research on the possible use of phytopathogens in the biological control of some other weeds is reviewed.     

Leafminers in vegetables,ornamental plants and weeds in Indonesia: Surveys of host crops,species composition and parasitoids

Extensive surveys of vegetable, ornamental and weedy plant species were conducted in highland and lowland vegetable production areas in Indonesia with the aim of recording leafminer species present and their associated natural enemies. The most common dipterous species reared from samples was the pea leafminer, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae). This introduced pest was particularly serious in highland vegetables in Java, Sumatra and South Sulawesi, causing yield losses as high as 60-70%. Another alien species, the vegetable leafminer, Liriomyza sativae Blanchard, contributed to problems in lowland areas on the north coast of West Java, where cucumbers were heavily damaged. An Asian leafminer species, Chromatomyia horticola Goureau, was more common in snow peas (Pisum sp.). Intensive sampling of leafminer-infested leaves from surveyed host plants yielded 11 species of hymenopteran parasitoids: 10 eulophids (Asecodes sp., Chrysocharis sp., Cirrospilus ambiguus (Hansson and LaSalle), Closterocerus sp., Hemiptarsenus varicornis (Girault), Neochrysocharis formosa (Westwood), Neochrysocharis sp., Pnigalio sp., Quadrastichus sp., Zagrammosoma sp.) and 1 eucoilid (Gronotoma sp.). The most abundant parasitoid species was H. varicornis. Levels of parasitism varied among crops and growing seasons, but were usually low, especially on potato (< 3%). Surveys revealed that most farmers (63%) attempted to control leafminers by applying insecticides twice weekly although these applications were neither effective nor economical according to responses of about 72% of the farmers. An integrated pest management approach is suggested that emphasizes IPM training for vegetable farmers and includes reductionor elimination of broad spectrum chemicals that would adversely affect parasitoids that may already be present as well as those that may be introduced. The initiation of a classical biological control programme is recommended to enhance the limited parasitoid complex present in Indonesia and increase levels of biological control.     

Prey stage preference,mutual interference and switching of Amblyseius swirskii (Acari: Phytoseiidae) on Eotetranychus frosti (Acari: Tetranychidae) and Cenopalpus irani (Acari: Tenuipalpidae)

Abstract

Prey stage preference, mutual interference, and switching of Amblyseius swirskii Athias-Henriot on Eotetranychus frosti (McGregor) (Tetranychidae) and Cenopalpus irani Dosse (Tenuipalpidae) were evaluated under laboratory conditions on apple leaves. The results of no-choice experiments on the two prey revealed that the predator A. swirskii consumed significantly more eggs than other prey stages. The predator consumed about 46% and 57% of the initial density of eggs of E. frosti and C. irani, respectively. In choice experiments the mean consumption rate of A. swirskii females significantly differed among each of the pests’ life stages. The negative value of the interference coefficient in the mutual interference analysis showed an inverse relationship between the predator density and per capita searching efficiency. The prey preference by predator was not dependent on the relative abundance of prey, as it did not switch from of E. frosti when it became rare to another prey which was more abundant except for the ratio 20E. frosti:60C. irani. The results of this study revealed that A. swirskii could be utilized as an effective predator in the integrated management of E. frosti and C. irani; particularly, its heavy preference for E. frosti could play a considerable role in control of it.