ABSTRACT. The use of biostimulant compounds in forestry and agriculture offers significant opportuni for farmers, according to findings from current university researc ! and field trials. Improved root and shoot growth, better stress resistance, better root growth potential, and reduction in nitrogen levels of fertilization are some of the possibilities that these compounds connote to sustainable agriculture.

This paper is an analysis of the distribution of areas of high species richness and endemicity based on dung beetles living in the different Holdridge life-zones of Costa Rica by using a geographic information system (GIS). Endemism was examined in relation to whether the species were shared with Nicaragua and/or Panama, or if they were strictly Costa Rican. The species composition of dung beetle distributions in the sampling areas and life-zones was evaluated. Species distribution was also analyzed in relation to altitudinal levels. The species richness and endemicity maps served as a base for doing a gap analysis and defining four different levels of high priority conservation areas. We also investigated what percentage of these priority areas is under some type of protection or conservation scheme and which of these areas should be enlarged. Also considered is the feasibility that these areas under protection have for enlargement, considering possible problems and interactions with present land-use. We include a list of all the recorded dung beetle species for Costa Rica, as well as their presence in the different Holdridge life-zones and their endemicity status. This study clearly demonstrates the need to include insects in biodiversity-endemicity studies because different and more detailed results are obtained in relation to vertebrate and plant-based studies.

The use of pollarded Erythrina poeppig&na as shade tree in coffee plantations is apparently an old practice in Costa Rica. The tree is not native to this country but was introduced between late 19th and 20th century and was rapidly dispersed in the coffee and cacao areas. Currently, the Erythrina tree is widespread in the Turrialba Valley (elevation 600-1300 m) and in the Central Valley (elevation 1200 m) where the species is always associated with present or past coffee crops. Pollarding carried out by Costa Rican farmers constitutes a long dated and functional practice, hence the objective of this study was to evaluate the amount of biomass produced by pollarding of Erythrina poeppigiana used as shade in coffee crop planted at a density of 280 trees/hectare under different pollarding frequencies. Results showed that by poUarding once a year, 18,470 kg of dry matter per hectare are produced; with two pollardings per year 11,800 kg/ha are produced and with three pollardings per year 7,850kg/ha are produced. The total amount of nitrogen removed is very similar for pollarding once and twice a year, but is lower for three times a year. The amount of nitrogen removed was approximately 230 kg/ha/year in the first two cases and 170 kg/ha/year in the last one.The above observations suggest that a considerable supply of nutrients exist in the systems with shade trees, when they are periodically pollarded.Finally some conclusions and follow up activities related to research on the species are suggested, such as higher biomass production techniques, appropriate planting practices, selection of genetic material, nutrient depletion when biomass is harvested, conversion of leaves to marketable feed sources (flour, pellets), alley cropping and green manure production and restoration of degraded areas and improductive savannas by planting large cuttings that would improve the soil by adding biomass and shade out undesirable grasses. *This work is part of a Ph.D. Dissertation submitted to the Southeastern University, New Orleans, Lousiana by R.O. Russo.

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Over the past decade there has been a notable increase of research on the use of naturally derived or organic materials in agriculture (Poincelot, 1986; Russo and Berlyn, 1990). Some of these are biostimulants, i.e., nonnutritional products that may reduce fertilizer use and increase yield and resistance to water and temperature stresses. Among the materials that stimulate plant growth in relatively small amounts (Aitken et al., 1964; Berlyn and Russo, 1990; Kinnersley et al., 1989; Senn, 1987; Senn and Kingman, 1973) are humic acids, marine algae, polymers of lactic acid, B vitamins, and ascorbic acid. Under certain conditions, biostimulants work well (Russo and Berlyn, 1990) and suggest possible uses in horticulture. We tested "Roots" (Lisa Products Corp., New Haven, Conn.), a proprietary mixture of humic acids, marine algae extracts, thiamine, and ascorbic acid. The objective of this study was to assess the effectiveness of this organic biostimulant (OB) on pod production of green beans (Phaseolus vulgaris L.). Seeds of beans cv. Bush Blue Lake 274 (Agway Inc., Syracuse, N.Y.) were sown and germinated in trays filled with vermiculite. In test A, the first set of 120 seedlings was transplanted, one seedling per pot, to 2.8-liter pots that contained a 1 potting soil (Agway) : 1 vermiculite (v/v) mix. The statistical design was a completely randomized factorial (Statview II, Abacus Concepts,