Alternaria solani caused the black disease tested on the plants taken from the family Solanaceae. It is well known for its damages caused on tomato. This paper deals with the efficiency of some fungicides which are considered, according to basic features of active substance, to be used for pests control. The efficiency of investigated fungicides is different and it depends on both parasites conditions and the tomato varieties, as well as the fungicides, the numbers of treatment and the pause between the treatment as well.

Field and greenhouse experiments were conducted to determine the response of eastern black nightshade (Solanum ptycanthum), black nightshade (S. nigrum), and tomato (Lycopersicon esculentum Mill. cv. Heinz 6004) to water stress and the effect of nightshade-tomato competition on soil water content. In the greenhouse, plants were exposed to three water regimes induced by watering either daily, weekly, or biweekly. Water deficit caused a similar decrease in height, weight, and leaf area in all three species. There was more than a 50% reduction in height when the plants were watered biweekly compared with daily watering. Water stress caused a shift in biomass from shoots to roots in all three species. Black nightshade and tomato produced thinner leaves in response to water deficit. Companion field experiments were conducted during the 1989 and 1990 growing seasons in Urbana, Ill. Eastern black nightshade and black nightshade were transplanted at densities of 0.8, 1.6, 3.2, and 4.8 plants/m2, 5 days after tomatoes were transplanted. These nightshade densities caused significant reductions in soil water content. In 1989, only the highest density of either nightshade species reduced topsoil water content. In 1990, all densities of nightshade, except the two lowest densities of black nightshade, reduced topsoil water content. Eastern black nightshade consistently had a greater effect on tomato yield than black nightshade. Tomato yields averaged over both years were 17,000 and 8,000 kg.ha-1 at the highest (4.8 plants/m2) density of black and eastern black nightshade, respectively. The decrease in soil moisture from high densities of nightshade could not account for the reduced yields.

Growth of tomato seedlings (cv. Bonny Best) in rooting substrate amended with the dinitroaniline herbicide, dinitramine (1 ppm in sand/Pro-mix, 1:1 or 1:2, v/v), caused a suppression in bacterial wilt symptoms caused by the Pseudomonas solanacearum strain K60. Dinitramine was not inhibitory to P. solanacearum in in vitro assays nor did it restrict multiplication of the pathogen in treated plants. Dinitramine also caused a decrease in the severity of bacterial canker, caused by Clavibacter michiganense subsp. michiganense JD83-1, but had no significant effect on the severity of bacterial speck, caused by Pseudomonas syringae pv. tomato DC894H. Resistance was not induced by a similar exposure of plants to the herbicides ethalfluralin or oryzalin. Resistance to Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici, was induced by exposure of seedlings to the herbicides dinitramine, ethalfluralin, and oryzalin. Acetochlor induced resistance towards Fusarium wilt but did not towards bacterial wilt. Exposure of plants to the dinitroaniline herbicide, trifluralin, did not induce resistance towards either bacterial wilt or Fusarium wilt in our experiments.

Internal bruising (IB) caused by handling impacts results in disruption of normal ripening in tomato (Lycopersicon esculentum Mill.) locular gel. It was selected as an injury indicator to investigate the effect of drop height (0, 10, 20, 30 cm) onto an unpadded surface and number of impacts (one or two) for three tomato cultivars. For mature-green (MG) tomatoes, significant incidence of IB (5% to 45%) was found in all cultivars for single drops on opposite sides of fruits from 20 cm; two drops on the same location from 20 cm caused 20% to 30% IB. Breaker-stage (BR) tomatoes were more sensitive to impacts than MG. Single drops from 10 cm on opposite sides of BR fruits caused 15% to 73% IB, depending on cultivar. Two drops on a single location from 10 cm caused 50% to 68% IB. 'Sunny' was less susceptible to IB than 'Solar Set' or 'Cobia' (formerly NVH-4459).

Tomato plants were grown in a calcareous soil supplemented with two organic wastes (sewage sludge and epicarp-mesocarp of the almond tree fruit). They were irrigated at three levels of salinity caused by the addition of sodium chloride, N, P, K, Na, Ca and Mg were determined in the soil and tomato fruits. The treatments had a significant incidence on mineral content in fruit and soil.

Tomato has been an important vegetable crop with high potential production for import-substitution and export purposes since the Sixth National Economics and Social Development Plan (1987-1991). But, tomato plantation faces serious problems of insect damage and several diseases, especially tomato root and stem rot caused by Sclerotium rolfsii Sacc. The main objectives of this research are to analyze the cost and revenue of tomato production and to study the possibility of production Trichoderma powder in commerce to be used to control such tomato root and stem rot disease. The results of the study showed that average production cost and revenue of tomato was estimated at about 6,518.89 and 8,416.03 baht per rai, respectively. The possiblity of production Trichoderma powder has some potential by comparing economic loss of the disease with the expenditure of using the powder and its efficiency to control the disease; and comparing average production cost, output quantity and net profit in case of using with and without using the powder. However, such possiblity potential will be low or high depends upon several factors, such as tomato's sales price, Trichoderma powder's potential demand, the powder's efficiency to control Sclerotium Root and Stem Rot of tomato and to control diseases of other crops and promotional sales cost of the powder.

1. Tomato plants, cultivar "Momotaro", were grown in Nutrient Film Technique with three levels of NH4-N concentrations, in connection with two light intensities (0% shading and 25% shading). 2. The worst plant growth was obtained at the highest NH4-N concentration under two light conditions. 3. The highest NH4-N concentration caused blossom end rot of tomato fruit, consequently resulted in the lowest yield under the 2 light conditions. Fruits from plants grown in the higher NH4-N concentration had higher sugar content. 4. The absorptions of calcium and magnesium by tomato plant were considerably restricted by the addition of NH4-N in the nutrient solution. 5. Nitrogen content in plant tissue increased with increasing NH4-N concentration in the nutrient solution. Whereas, Ca and Mg contents in the plant decreased with increasing NH4-N concentration. 6. Under the shade condition, keen competition for assimilates was observed between upper shoots and fruits in the first cluster during fruit development. 7. The addition of NH4-N to nutrient solution resulted in increasing plant growth and fruit quality. Further additional NH4-N, however, caused marked decreases in fruit yield.

Twenty-two isolates of Fusarium oxysporum, from Queensland's major tomato growing areas, were studied in glasshouse pathogenicity tests and assessed for vegetative compatibility. Isolates of Fusarium oxysporum f. sp. lycopersici were identified to race using pathogenicity tests with 4 differential tomato cultivars. The occurrence of race 3 in the Bundaberg district in 1988 was established. In glasshouse experiments, Fusarium wilt severity was influenced by inoculum concentration (1 million v. 5 million conidia per mL). Pathogenic and non-pathogenic isolates were distinguished by vegetative compatibility group analysis. However, all races were in a single vegetative compatibility group and could not be differentiated using this technique. Isolates collected from discoloured vascular tissue in the lower stems of plants with severe root rot (Pythium spp. associated), were non-pathogenic to tomato, bean and pea, although some isolates caused slight damage to cucumber. These isolates were distinctly different from Fusarium oxysporum f. sp. radicis-lycopersici, the cause of root and crown rot.