K. Sonder et al., THE FREQUENCY OF INVERTEBRATES IN FIELDS OF POTATOES AND CARROTS GROWN UNDER INTENSE CONDITIONS IN A HIGHLAND AREA OF PANAMA, Zeitschrift fur Pflanzenkrankheiten und Pflanzenschutz, 104(1), 1997, pp. 96-101
Studies were conducted from June to November, 1994, in the Cerro Punta
area (Chiriqui, Panama) on volcanic soils at altitudes of 1.800 to 2.
300 m above sea level, in the rainy season (May to December). Inverteb
rates were monitored by pitfall traps. The intensity of pesticide spra
ying was inquired from the farmers at the end of the study period and
compared with data published so far. In potatoes (50 % of the agricult
ural area) per 120 days from planting to harvest, one nematicide, one
herbicide, 13 fungicides and 19 insecticides were applied at the avera
ge. Every field in tile area received more than 26 insecticidal sprays
per year, but an examined farmer (Ing. agr.) sprayed insecticides at
maximum 15 times, only. Collembola were by far the mast common inverte
brates. Of predatory arthropods, six orders were present in the fields
, but all at very low frequency (with no significant difference betwee
n crops, adding up to 0.25 specimens per trap per day). Studies from o
ther regions of partly high insecticide input confirm the negative eff
ects of a high frequency of insecticidal sprays on the beneficial arth
ropods. The necessity of training Farmers in plant protection is stres
sed.