Author : Alberto, Ronaldo T.

Summary : Studies were conducted over a one year period with five specific areas investigated: The existing species and population of different plant pathogens and insects pests, abundance and succession of insect pests and diseases on different growth stages of crops; disease incidence and population of pathogens on different cropping patterns after pesticide treatments; pesticide residue in soil, air and plants as a consequence of pesticide application, and pesticide management practices employed by the farmers. In white onion-pepper, red onion-rice, cabbage-corn and red onion-corn cropping patterns, white and red onions were attacked by Fusarium and Sclerotium bulb rots; pepper by bacterial soft rot and anthracnose; rice by rice root knot, and bacterial leaf blight; corn by Helminthosporium leaf spot, Curvularia leaf blight and leaf rust diseases while cabbage remained disease free. White and red onions were infested by Spodoptra sp. and Liriomyza sp. Bemicia tabaci, Aphis gossypu and Nirvana sp. Rice by Tryporyza incertulas, Leptocorisa oratoria, Nephotettix sp. Oxya sp. and Cnaphalocrosis medinalis. Cabbage by Plutella xylostella, Crocidolomia binotalis, Spodoptera litura and five minor insect pests. Corn by Ostrinia furnacalis and other insect pests of minor importance. Monocrotophos treated white and red onions showed low incidence of Fusarium and Selerotium rots compared to the untreated onions. Pepper showed high disease incidence of bacterial sofr rot but it had low incidence of anthacnose and stem rot whiel rain fed rice heavily infested with rice rootknot nematodes and had low incidence of bacterial leaf blight. Cabbage treated with both monocrotophos and pesticide mixture was free from any disease whereas corn was infected by Helmithosporium and Curvularia leaf spots and rusts. Monocrotophos treated and untreated white and red onions had low population of insect pests. The same was true with pepper and rice. Plutella xylostella, Crocidolimia binotallis and Spodoptera sp. were present at low population level in the monocrotophos treated cabbage, but high in the untreated. Cabbage treated with combination of methamidophos, cypermethrin and bendiocarb had lower insect population than in monocrotophos treated plants. In corn, Spodoptera sp. had the highest population per plant followed by Ostrinia furnacalis. Application of monocrotophos and pesticide mixture resulted in low nematode population, variable effects on the air-borne fungi, and growth inhibition of soil fungi and bacteria. These soil fungi were Cephalosporium sp, other species of Aspergillus, Curvularia and unidentified species of fungi. The soil bacteria were Pseudomonas sp, all species of Bacillus and other unidentified bacterial species. Population of the rest of the species increased. Population counts of Curvularia, species of Bacillus and other unidentified bacterial species decreased when exposed to pesticide mixture. Population of the rest of the species increased. Bongabon farmers were totally dependent on chemical pesticides to control pests. They used monocrotophos and other pesticides that are not registered for the crops grown. The farmers applied pesticides on calendar basis at a high dosages and unprotecte by any protective gears. Pesticide residues in the treated plots exceeded the maximum residue limit set by the WHO/FAO in the atmosphere, soil, and cabbage heads but low in onion bulbs. Pesticide mixture were applied in cabbage every two days while monocrotophos was applied at 3-4 times per cropping season in onions. Re-entry and pre-harvest intervals were 3-4 hours after spraying and 2-3 days after the last insecticide application, respectively. Proper pesticide storage and disposal was not observed. Empty pesticide bottles were sold in junk shops or left in the field. Sprayers were washed in irrigation canals or creek. Pesticide poisoning was generally suicidal in nature and others were occupational and accidental. Cases involved were mostly male farmers under age group level of 11-20 years old. The usual pesticide poisoning symptoms were dizziness, headache, nausea, chest pain, salivation and difficulty in breathing.