Ground water pollution due to aquaculture in east coast region of Nellore district, Andhrapradesh, India

Ground water quality parameters were studied for pollution due to aquaculture in the east coast region of district Andhrapradesh, India. Over a period of two years, 46 groundwater samples were collected for analyses. The results showed that the alkalinity ranged from 120 - 482 mg/L, and pH ranged from 7.1 to 8.6. The chloride concentration ranged from 65 – 4950 mg/L, Dissolved Oxygen (DO) was 2 to 8.4 mg/L, and Biochemical Oxygen Demand was 3 to 23 mg/L. Conductivity ranged from 68 to 8200 umho/cm. Approximately 86 % of water samples exceed the international chloride standards for drinking water (200 – 250 mg/L). The Dissolved Oxygen (DO) concentration was within the acceptable standards of 6 mg/L. The DO concentration of the ground water satisfied the DO requirement for aquaculture. However, open well number 12 has less (3.1 mg/ml), potentially indicating contamination from aquaculture farm effluents. Low concentrations of Dissolved Oxygen in nearby well water provided further evidence that these wells are contaminated with biodegradable organic compounds. The effect of aqua farms on the ground water quality was discussed in line with public health standard.Key words: Ground water pollution, aquaculture, water quality, physical-chemical, Parameters

Effects of crude extracts of Allium sativum Linn, Cymbopogon citratus (CD) Stapf and Terminalia catappa L. on rotcausing fungi of Dioscorea species

Fungitoxic effects ofAllium sativum Linn., Terminalia catappa L. and Cymhopogoll citratus (DC) Stapf. on four rot-causing fungi (Aspergillus niger, Fusarium oXysporum and Penicillium oxalicum, Botryodiplodia Iheobromae) of stored yam tubers were studied in vitro. Pathogenicity test revealed that A.<,pergillus niger. Botryodiplodia theobromae, Fusarium oxysporum and Penicillium oxalicum induced rot in healthy yam tubers after] 0 days of fe-inoculation, with B. theobromae as the most virulent. Four different concentrations of each plant extract were obtained by blending 25g, 50g, 75g, and 100g of each plant part in 100 ml of sterile distilled water (SDW). A. sativum extracts had effective inhibitions on the mycelial growth of all fungi ranging from 31.1% -92.4%. Extracts of T. catappa and C. citratus showed between slight to moderately effective inhibitions ranging from 3.0% to 46.7% respectively. The effects of T. catappa and C. citratus extracts on the mycelial growth of B, theobromae was stimulatory rather than inhibitory at all concentrations while A. sativum proved just slightly inhibitory at higher concentrations. The most fungitoxic of all the extracts was A. sativum at 10% concentration which showed significant (P < 0.01) inhibitions on all the fungal pathogens investigated indicating its potential as a natural fungicide against rot common in yams while in storage

Fungal isolates of groundnut (Arachis hypogaea L) seeds in Owerri Metropolis, Nigeria

Groundnut, an important crop grown in Nigeria, is highly susceptible to diseases caused by some plant pathogenic fungi, thereby leading to loss of yield. Isolations were made from fungi-infested groundnut seed samples. Four seeds from each sample were aseptically plated on Potato Dextrose Agar (PDA). Pure isolates were identified using cultural and microscopic characters, then stored in agar slants until they were ready for use. Data were statistically analysed using analysis of variance (ANOVA). Results of isolation identified six fungi associated with groundnut seeds to include Aspergillus flavus (88.90±19.22%), A. parasiticus (44.43±19.28%), A. niger (100.00±0.00%), Penicillium chrysogenum (44.43±19.28%), Trichoderma virens (33.30±0.00%) and Chrysonilia sitophila (77.80±19.22%). The percentage occurrence of A. niger was found to be the highest followed by A. flavus and C. sitophila. These fungi were found to be associated with groundnut seeds in storage. Therefore, good sanitary measures and planting of resistant varieties of groundnut should be used to prevent spoilage of groundnut seeds