Technological Economics of Crop Protection and Pest Control

Abstract

THE SCIENTIFIC PRINCIPLES OF CROP PROTECTION. Dr Hubert Martin. Edward Arnold (Publishers) Ltd, London, 1973. ISBN 07131 2382 6. pp. viii + 423. Price £12.00.

APHID TECHNOLOGY. Edited by H. F. van Emden. Academic Press, London and New York, 1972. ISBN 0 12 714150 2, pp. xiv + 344. Price £6.00.

BIBLIOGRAPHY OF THE APHIDIDAE OF THE WORLD. Clyde F. Smith Technical Bulletin No. 216 North Carolina Agricultural Experiment Station, 1972. pp. 717. Price not given.

THE AUSTRALIAN SELECTIVE WEED CONTROL HANDBOOK 1973. J. T. Swarbrick. Herbicide Recommendations, 3A Ipswich Street, Toowoomba 4350, Australia, pp. 203. Price not given.

GUIDE TO HAND-OPERATED AND ANIMAL-DRAWN EQUIPMENT. Intermediate Technology Development Group, London. pp. 84. Price £1.50.

NITROGEN FERTILIZATION AND MANAGEMENT IN TROPICAL RICE. P. A. Sanchez. North Carolina Agricultural Experiment Station Technical Bulletin No. 213, 1972. pp. 31.

TROPICAL PEST BULLETIN No 2. Analytical method for assessing yield losses caused by pests on cereal crops with and without pesticides. E. Judenko. The Centre for Overseas Pest Research, College House, Wrights Lane, London W8 5SJ, 1973. ISBN 0 85135 061 5. Price 40p. pp. 31     

FAO Crop Protection Activities in Cereal Growing2

FAO is responsible for various projects in cereal growing that have a crop protection component. Within this the overall approach followed is along the lines of integrated pest control. The following field activities are briefly reviewed: research on and control of grain-eating birds; breeding for stable resistance in wheat; integrated pest control in sorghum and millet; integrated pest control in rice-growing in South and Southeast Asia; reduction of post-harvest losses. The effective application of new plant protection technology depends on a better understanding of the agro-ecosystem concerned in order to make maximal use of knowledge collected elsewhere.     

The Effects of Cultural Measures on Cereal Pests and Their Role in Integrated Pest Management

The influences of cultural control measures on invertebrate pests and their natural enemies in cereals (wheat, barley and oats) are described and discussed, with emphasis on the major pests in north-west Europe. Possibilities for additive and synergistic combinations of cultural measures are identified, together with opportunities for integrating cultural measures with chemical and biological control where appropriate. Recent studies confirm the central role of cultural control measures in integrated pest management and integrated production of cereal crops. However, cultural measures often have opposing effects on different pests as well as diseases and weeds, so that appropriate measures must be selected on the basis of an assessment of the risks from key pests, diseases and weeds. Crop rotation is not an important means of controlling cereal pests, but its use is recommended for control of cereal diseases and weeds, as well as pests of crops grown in rotation with cereals. Diversification of crops and non-crop habitats in predominantly cereal growing areas is thought to increase numbers of certain parasitoids and polyphagous predators of cereal pests. The presence of weeds or an intercrop in a field together with cereals may reduce the severity of aphid and slug damage to cereals. Trap cropping has not yet been adequately tested in wheat, barley or oats. Cover crops reduce damage by wheat bulb fly in a following wheat crop, but increase the risk of slug damage. Resistance to a wide range of cereal aphid species has been identified in wheat and barley, but in Europe, more emphasis is placed on selecting cultivars with resistance to cereal diseases rather than pest resistance. Resistance in wheat to wheat bulb fly and wheat blossom midge is recorded, and resistance to slug damage has been reported in some laboratory studies. Early sowing of winter cereals results in more damage by certain dipterous pests and increased numbers of the aphid vectors of barley yellow dwarf virus (BYDV), but early sowing results in less damage by wheat bulb fly and slugs in autumn/winter and by late infestations of aphids in summer. Avoidance of ploughing results in reduced incidence of wheat bulb fly, yellow cereal fly and aphids, but increased numbers of slugs, wheat blossom midge and bibionid larvae. Avoidance of ploughing can result in greater numbers of certain polyphagous predators, particularly in the first weeks following crop establishment. The presence of straw residues results in increased slug populations, but reduced incidence of yellow cereal fly and wheat blossom midge. Preparation of fine, firm seedbeds discourages attack by slugs and wheat bulb fly on cereals. Drilling at slightly greater depth in rough cloddy seedbeds helps to protect wheat seeds from slug damage. Nitrogen fertiliser applied in spring can help cereal plants compensate for losses by wheat bulb fly or slugs. However, nitrogen applications tend to result in increased summer infestations of aphids.     

Systems Analysis Applied to Crop Protection1)

This paper reviews the biological problem of crop protection from a systems analysis point of view, and discusses the commonalities in the biological and mathematical form of the population models used to describe the interactions between trophic levels (e.g. herbivore–plant). The historical development of the mathematical models is presented. The uses of these models in crop production are discussed.     

Fungi and the Decrease of Cereal Cyst-nematode Populations in Cereal Monoculture1

Populations of the cereal cyst-nematode decrease when cereals are grown frequently or continuously because the females that develop on the roots between May and July fail to produce eggs, or produce a smaller number than expected. Consequently, cysts in the soil after harvest are fewer and contain fewer eggs. The role of fungal parasites and competitors in limiting populations of cyst-nematodes is reviewed. Parasites of eggs and females of Heterodera avenae Woll. were widespread in British cereal fields, an Entomophthora-like fungus and Verticillium chlamydosporium Barron & Onions being the most common species found. Although fungal parasites may be the cause of the failure of the nematode to increase, it has not yet been established unequivocally.     

Cereal Cyst Nematode, Soil Heating and Fungal Parasitism1

Experiments on winter heating of cereal cyst nematode-infested soil have been carried out during 4 years on light loam in eight concrete pipes (l-m diam.) dug into the soil. The soil in four of the pipes was heated to a temperature of 5oC during the winter periods. Temperature was measured at a depth of 5 cm. The heating was carried out by means of buried electrical cables. Soil temperature in the remaining pipes followed the natural fluctuation. The host plant was Sun II oats. Statistical analysis of the results for all the years together showed that the propagation of nematode populations was significantly lower in heated than in non-heated plots. Investigation of soil samples in spring and autumn 1980 for eggs and larvae, as well as fungal parasitism of these, showed that numbers of eggs and larvae were significantly lower in heated than in non-heated plots and the percentage of parasitized eggs and larvae was significantly higher in heated than in non-heated plots. Verticillium chlamydosporium seems to be a main parasitic fungus.     

Twenty-ninth International Crop Protection Symposium,Gent, Belgium,May 1977

Abstract

A new simple mass rearing technique for Heliothis armigera is described. Based on environmental and spatial considerations, the technique employs a semi‐artifical diet in conjunction with group rearing at all stages of development and obviates the need for individual handling of eggs, larvae and adults.     

Cereal Cyst Nematode and N Fertilization1

The effect of increasing amounts of nitrogen on the propagation of the cereal cyst nematode was studied. Nitrogen applications as nitro-chalk ranged 0–1,500 kg/ha (0–232.5 kg N/ha). Maximum propagation was obtained at about 46.5 kg N/ha. Increasing N doses reduced propagation to about 1/2 - 1/3 of the maximum. Two factors seem to be involved: 1) reduced fertility of females with increasing N application and 2) apparently fewer females developed with N applications greater than 46.5 kg/ha. Hatching in solution of calcium nitrate decreased with increasing concentration.     

The Role of Forecasting in Crop Protection Decision Making: an Economic Viewpoint1

In making crop protection decisions, farmers have to answer two questions: what type of control measure(s) should I adopt? How should I apply this (these) measure (s), when, how frequently, etc.? The answer to these questions will depend upon: a) the dimensions of pest attack and the damage it causes, b) farmers' goals, c) the range of protection measures available to them which they can use, and d) the information available, in the form of monitored and forecast information. It is within this context that the role of forecasting is considered. An analysis is made of the possible impact that forecast infomation can have on farmer decision-making, particularly with regard to the accuracy of the forecast and the time at which it is available. This leads on to the problem of assessing the value of a forecast at a regional level, against which the costs of providing such information can be set. Finally, situations in which forecast information is likely to be of greatest value (and of least value) are identified, and implications are drawn concerning the institutional and other changes that could be taken to allow better use to be made of forecast information. Lorsque les agriculteurs decident de proteger leurs cultures, ils doivent repondre aux deux questions suivantes: quel est le mode d'intervention a choisir et comment, quand et a frequence faut-il intervenir. La reponse dependra notamment: de I'etendue de I'infestation et de L'importance des deglts; des buts que s'est assignes L'arboriculteur; de la gamme de methodes dont il dispose; des previsions qui lui sont fournies. La prevision est condideree dans ce cadre, puisqu'elle est susceptible d'infuler sur les decisions de L'agriculteur dans la mesure ou elle est etablie avec precision et au bon moment. I1 est donc utile d'evaluer L'inter6t economique d'une prevision regionale en faisant intervenir le cofit de celle-ci. Enfin, il est fait etat de situations dans lesquelles la prevision est profitable ou non. Suivant les cas, certaines modifications structurelles peuvent s'imposer afin de mieux tirer benefice des previsions.     

Crop Rotation,Monoculture and Soil Ecology1

Crop rotation and monocultural systems are discussed in relation to disease management and control. The ecological basis of both systems is examined. In crop rotation the leading principle is that in the absence of host-plants parasite populations invariably decline below threshold levels, mostly within a few years. Knowledge of the behaviour of parasite populations in the soil is becoming vast, especially in the case of plant parasitic nematodes. Analysis of soil samples for nematodes and fungi often helps the farmer to plan rotation schemes. From the ecological point of view, crop rotation is interpreted as a system of interrupted monocultures. Monocultural practices cannot be applied so universally as crop rotation, but in a number of cases monoculture is feasible, e.g. with cereals. In the equilibrium situation between host-plant (e.g. cereals), parasite (Gaeumannomyces graminis [Sacc.] v. Arx & Olivier) and the antagonists of the parasite, growth of the crop is satisfactory. These cases illustrate the role of antagonists, and it is proposed to investigate more systematically monocultures in relation to antagonisms. This may lead to more opportunities for biological control of soil-borne diseases.     

伊犁河经济鱼类的开发与保护

我国伊犁河现有鱼类３２种，其中经济鱼类１５种，被捕捞利用的９种。一些移植鱼类成为我国伊犁河的特有鱼类，如：欧鲇、赤梢鱼、裸腹鲟等开发利用潜力较大。本文就伊犁河经济鱼类的开与资源保护进行了论述。