ORGANIC amendments in the soil suppress diseases, increase plant growth, help reduce the risk of environmental pollution and result in chemical-free production of crops. Therefore, implementation of this technology is the need of the hour.

The per acre yield of many crops in this country are not equal to those obtained in other countries. However, there are ample opportunities for boosting production of cereals, sugar and fibre crops as well as oilseeds, pulses, fruits and vegetables, due to favourable climatic conditions and fertility of the soil here.

The causes of low crop production are many, but attack of diseases is certainly one of the main reasons. The crops suffers from a number of diseases caused by fungi, bacteria, nematodes, viruses, phytoplasmas and a-biotic factors such as low or high temperature, humidity, day and night length, deficiency and excess of nutrients, environmental pollution etc. The losses in yield are increasing vigorously due to different diseases and other abnormalities, which some times are hundred per cent.

The crops are susceptible to many diseases due to multiple cropping pattern, continued presence of host and pathogens (disease causing agents) and because of many other reasons including environment favourable for growtht of diseases.

The use of genetically resistant plants is one of the most effective approaches to disease management. Whereas, exclusion, elimination, or reduction of inoculums of disease causing agents are the disease management measures and the use of chemicals is very effective in the disease management. But their utility is limited due to higher costs, non-availability, environmental pollution and residual problems.

Control of the diseases may include crop rotation, planting resistant varieties when available or sowing or planting of certified or disease-free seeds or seedlings, timely sowing, planting in well-prepared fertile soil, controlling weeds and insect pests and practicing clean plough down after harvest.

Incorrect identification of diseases may lead to the use of wrong management practices which may cause wastage of time, expenses and failure of crop.

According to reports the use of flooding, deep ploughing, mulching and crop rotation reduces populations. A of disease causing organisms through an integrated control experiment. Judicial use of irrigation water and fertiliser application, mix or trap cropping and weed management are other measures of controlling diseases.

Scientists have also evaluated amendment of different organic manures (cakes of oilseeds and neem, poultry manure, spent mushroom compost, farm yard manure and biogas slurry, fresh and old leaves, other plant residues and debris) against different diseases and have reported that the pathogen population reduced significantly in amended soil in comparison to the untreated control. It is found that these amendments significantly improve plant growth parameters and suppress disease infections. The researchers have also recommended the use of botanical pesticides or phytonicides or phytopesticides as the easy and cheap approach for the control of diseases as compared to chemicals.

As a result of several years research on the aspect, the scientists have developed a sensible, rational and effective integrated management strategy against diseases by using the leaf, seed and seed kernel extracts and straws of crops, by using alone and in combination on the plant growth and multiplication of disease causing organisms, and reported better results by exploring that the extracts at higher concentration showed maximum plant growth and significantly suppressed the disease. It is also reported that aqueous extracts of some weed species also causes substantial mortality of the plant pathogens in vitro.

Many research workers also studied the effects of agro-industrial wastes including press mud, molasses and rice husk, oilseed cakes and nematophagous fungi on the performance of plant growth and on the population of pathogens under greenhouse conditions and achieved good result with reference to management of diseases.

The studies on similar aspect were also carried out at the Department of Plant Pathology, Faculty of Crop Protection, Sindh Agriculture University, Tandojam. It was observed that the organic amendments with different oilseed cakes, crop residues and plant extracts significantly increased the plant growth and decreased the population of disease causing organisms. Therefore, it is recommended that organic amendments must be included in modern crop production technology, so that the better crop yield could be obtained without use of poisonous chemicals, most commonly applied for disease control. This will be economical for the growers and beneficial for consumers in a sense that organic amendments yield chemical-free crop including cereals, oilseeds, pulses, vegetables and fruits. This technology also helps reduce the risk of environmental pollution.

Good examples of chemical-free production: selections of disease free soil; • practice of crop rotation; sowing on flat bed/ ridges or as may be beneficial ; use of healthy seed; solar, hot air, hot water treatment of the seed and soil; using disease-free seedlings; dipping the seeds/roots of seedlings in plant extracts; sowing before or after at proper time as to be useful in case; practice satiation; weed and insect control through non chemical measures; avoiding development of potential hosts adjacent the crop; rouging out or pruning diseased plants or parts; preventive/curative use of plant extracts; following good soil fertility ; proper irrigation and drainage ; flood fallow; proper harvesting; better threshing; good transportation and best storage.

Preference should be given to monitoring but not to stop visiting the crop. Rely on science (by the farmers) and for the farmers. Adopt improved technology but do not repeat long-established ones. Be devoted to practical method. Theory needs to be tested in practice. Learn by doing but not by seeing, listening and reading only. Love insects but not pests. Forget pathogens but not beneficial ones. Encourage IPM but not pesticides. Train the farmers and the owners as well. Have faith in agriculturists but not in irrelevant people. Save the crops. Save nature for the future.