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The effects of four soil water potential regimes under greenhouse conditions on growth, development, and yield of 'Homestead selection' pawpaw were investigated. The objectives were to determine the critical soil water potential regime and the moisture sensitive stages of growth of pawpaw. Repeated cycles of stress to -6.0 bar soil water potential imposed as from vegetative phase prevented fruit formation by constantly causing flower abscission. The stressed plants were stunted in size. The -2.0 bar soil water potential value was considered the critical level for normal growth and reproductive development of pawpaw. The mid-vegetative, flowering and fruit enlargement phases were moisture sensitive.

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At Ibadan, southwestern Nigeria, papaya trees were imercropped with okra, watermelon, sweet potato, bush greens, jews' mallow and Solanum gilo Raddi. The aim of the experiment was to select crops suitable for intercropping in the alleys of papaya plants in orchards. Sweet potato and Solanurn gilo Raddi caused marked reduction in the yield of papaya. Land Equivalent Ration (LER) for papaya intercopped with okra, water-melon, sweet potato, bush greens° jews' mallow and Solanum gilo Raddi were 3.86, 3.13, 2.06, 1.86, 1.60 and 1.54, respectively; indicating that all the combinations were more advantageous than the monocrop of papaya. Monetary value of the mixtures, however, indicated that the inclusion of intercrops of sweet potato or Solanum gilo Raddi, is disadvantageous.Although intercropping in papaya orchards is beneficial, it should be limited to the early vegetative and late fruiting phases of papaya when the Leaf Area Index (LAI) of papaya is low. A relay of okra followed by watermelon or bush greens followed by jews' mallow (or sweet potato grown for fodder) is considered suitable for intercropping the alleys of papaya.

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At lbadan southwestern Nigeria, juvenile Agege I sweet orange (Citrus sinensis) trees were intercropped with cassava (Manihot esculenta Crantz) + maize (Zea mays L.), egusi melon (Citrullus lanatus L.) followed by soyabeans (Glycine max (L.) Merit), or chilli pepper Capsicum frutescence L.) + amaranthus (Amaranthus caudatus L.) for four consecutive years. The aim was to detennine an intercropping option which would yield high revenues without impairing the fruit yield of sweet orange. None of the intercrops significantly affected the height of sweet orange trees. However, all the intercrops significantly decreased the canopy diameter of sweet orange trees in the second year of intercropping. lntercropping with egusi melon followed by soyabeans, or cassava + maize significantly decreased the canopy volume of sweet orange trees. Intercropping with cassava + maize prevented early fruit set and significantly decreased fruit yield of sweet orange. Fruit yield of sweet orange intercropped with chilli pepper+ amaranthus did not differ significantly from the yields of monocropped sweet orange trees. Intercropping with chilli pepper + amaranthus gave the highest yield efficiency of sweet orange trees. Net Present Value (NPV) of sweet orange plots monocropped or intercropped egusi melon followed by soyabeans, cassava + maize or chilli pepper + amaranthus were N -37900, N -300, N 105900 and N 154300 respectively. Since intercropping with chilli pepper+ amaranthus gave the highest productivity without impairing fruit yield of sweet orange, this cropping system is recommended for adoption by citrus farmers in southwestern Nigeria.

Synthetic pesticides have been found to increase the yield of agricultural products over tenfold. However, the effects of pesticide misuse around the world include costly environmental pollution and disruption of the balance of nature in addition to their high cost and non-availability. Hence the need for search for alternative pesticide formulations to avert these undesirable effects. A study was conducted to evaluate the efficacy of Neem (Azadirachta indica A. Juss) leaf powder and organic fertiliser for management of M. incognita in soybean (Glycine max) production. A screenhouse experiment was conducted to test the efficacy of neem leaf powder (NLP) and organic based fertiliser (OBF), alone and a combination of 50% each of the NLP and OBF against root galling and Meloidogyne incognita multiplication on soybean and their potency in grain yield improvement. The experiment was laid out in completely randomised design with three replications. Although all treatments were effective in reducing root galling and nematode reproduction, NLP applied alone gave the highest reduction (92.59 %) in gall formation and nematode multiplication (82.07 %), followed by NLP + OBF and then OBF alone. Increases in grain yield ranged from 103.08 to 108.46% in response to organic soil amendment. Integration of the two organic substances is a better and more promising strategy since it reduced the quantity of organic fertiliser that had to be transported to farmer's field by 50%.