Dwight Robinson

Effects of shade and bird exclusion on arthropods and leaf damage on coffee farms in Jamaica’s Blue Mountains

AbstractsThe effects of overstory trees and birds on coffee pests are poorly understood. This study documents (a) the effect of bird exclusion on foliage-dwelling arthropod abundance and insect-caused leaf damage, and (b) the relationships between vegetation complexity and insect abundance, leaf damage, and prevalence of fungal leaf symptoms on coffee farms in the Blue Mountains of Jamaica, West Indies. Overall arthropod abundance was reduced inside bird-proof exclosures, and this corresponded to reduced insect-caused leaf damage. The reduction in leaf damage increased with greater shade, but fungal leaf symptoms increased with greater shade and proximity to non-coffee habitat patches. There appears to be a trade-off for coffee farmers in our study region: vegetation complexity may attract beneficial insect-eating birds that can reduce insect damage, but it is also associated with the prevalence of fungal leaf symptoms.

Insecticide Contamination of Jamaican Environment. IV. Transport of the Residues Coffee Plantations in the Blue Mountains to Coastal Waters in Eastern Jamaica

A survey of 120 coffee farmers in the Portland watershed revealed that they lacked training in pesticide application, and had no concept of the transport of residues in the environment and their impact on non-target organisms.Residues of organochlorine (OC) and organophosphorous compounds (OP) were monitored monthly for over a year in plantation soil, and water, sediment and fauna of three rivers and coastal waters of Portland watershed by gas chromatography. OP residues were not detected in any sample while OC residues were below detection levels in Rio Grande. The mean concentration ± standard error of residues detected in water (μg L_1), sediment (ng g_1) and fauna (ng g_1 in wet weight) were: α-endosulfan 2.7 ± 1.29, 3.8 ± 0.15 and 15.9 ± 1.61, respectively, in Spanish River, 1.56 ± 0.43, 24.3 ± 16.44 and 9.0 ± 1.86, respectively, in Swift River; 0.40 ± 0.02, 1.77 ± 0.68 ± 12.63, respectively, in sea coast; β-endosulfan, 1.2 ± 0.48, 0 and 8.1 ± 1.99, respectively, in Spanish River, 1.9 ± 0.49, 0.75 ± 0.32 and 11. ± 4.32, respectively, in Swift River; 0, 5.1 ± 0.30 and 30.9 ± 15.96, respectively, in sea coast; endosulfan sulphate, 0.12 ± 0.12, 4.8 ± 1.62 and 10.0 ± 2.02, respectively, in Spanish River, 3.6 ± 0.95, 3.1 ± 0.56 and 7.9 ± 1.29, respectively, in Swift River and 0, 3.9 ± 2.17 and 24.0 ± 14.67, respectively, in sea coast.Dieldrin residues were detected only once in water (0.2 ± 0.03) and sediment (0.02 ± 0.003) of Spanish River, water (0.76 ± 0.09) of Swift River and sediment (0.1 ± 0.005) of sea coast; pp′ DDE was found twice in water (3.1 ± 1.53) and sediment (0.1 ± 0.007) of Swift River and water (0.8 ± 0.22) and sediment (6.14 ± 0.41) of sea coast. Arochlor was detected only twice (0.011 and 0.153) in water of Spanish River.

Insecticide contamination of the Jamaican environment

Abstract The most frequently detected residues in soils, well and spring water, and in water, sediment and fish/shrimp samples from rivers and sea coasts across Jamaica, are endosulfans > chlorpyrifos > diazinon > dieldrin; these often exceed LC 50 values for many fish species. Mussels, sediment and water of Kingston Harbour had residues of eight organochlorines.

Insecticide Contamination of Jamaican Environment. V. Island-Wide Rapid Survey of Residues in Surface and Ground Water

Residues of organochlorines and organophosphates were determined by gas chromatography in water and sediment from 26 locations in 17 major rivers, 7 natural springs and 13 wells across Jamaica. Samples were collected on only one occasion between May and July, 1994. Residues of endosulfan were detected in all but three rivers; α-endosulfan in 15 samples of sediment (0.9–108.1, mean = 28.93, S.E. = 7.198 μg kg-1) and 13 of water (0.01–0.35, mean = 0.11, S.E. = 0.035 μg L-1), β-endosulfan in 5 sediment (15.29–49.35, mean = 30.56, S.E. = 7.132 μg kg-1) and 12 water (0.05–0.31, mean = 0.14, S.E. = 0.031 μg L-1) samples, and endosulfan sulphate in waters of three rivers (0.003–0.244 μg L-1). Chlorpyrifos was present in 9 sediment (0.423-135.2, mean = 18.38, S.E. = 10.699 μg kg-1) and two water (0.001–0.022 μg L-1) samples, diazinon and ethoprophos in the sediment of one river each. Mean levels (μg L-1) of α and β isomers and sulphate of endosulfan were 0.16 (S.E. = 0.057), 0.12 (S.E. = 0.036) and 0.15 (S.E. = 0.089), respectively, in four of the seven springs and 0.23 (S.E. = 0.052), 0.11 (S.E. = 0.029) and 0.26 (S.E. = 0.088), respectively, in seven of the thirteen wells monitored.

PESTICIDE CONTAMINATION OF JAMAICAN ENVIRONMENT. II. INSECTICIDE RESIDUES IN THE RIVERS AND SHRIMPS OF RIO COBRE BASIN, 1982-1996

Only organochlorine (OC) residues were monitored by gas chromatographyin water, sediment and shrimp samples collected everymonth between July 1982 and August 1983 from therivers of Rio Cobre basin. In samples collected everyfour months during 1989–1990, and seven times duringJuly 1995–March 1996, OC and OP (organophosphates)residues were monitored. Carbamate and pyrethroidresidues were not monitored. The detection ofresidues in 1982–1983 was 54 to 100% in water andsediment, and 83 to 100% in shrimp samples fromvarious sampling stations in the four rivers. In otheryears, it ranged from about 40 to 100% in the threetypes of samples.In 1982–1983, DDE and dieldrin residues were found tobe much higher than those of lindane and α- andβ-endosulfan in Black River, Rio Pedro, ThomasRiver and Rio Cobre in the watershed. The ranges ofmeans of each residue in water (μg L-1), sediment(ng g-1) and shrimp (ng g-1) samples, respectively, were:DDE, 0.059–102.0, 3.44–13.97, 0.344–14.57;dieldrin, 0.026–173.6, 1.21–2.75, 0.427–5.59;α-endosulfan, bdl, 1.75–4.00, bdl;β-endosulfan, bdl (below detectable limits), 2.51–9.48, bdl;and lindane, (bdl), 0.110–0.319, 2.90.In 1989–1990 and 1995–1996, residues of six OCs and two OPs were detected quite regularly. DDE, dieldrinand Chlorpyrifos residues were much higher than thoseof the other insecticides. The range of their meansin water (μg L-1), sediment and shrimp (ng g-1),respectively, were: DDE, 1.66–19.76, 0.941–5.84,1.11–8.32; dieldrin, 0.077–7.22, 0.425–3.31,0.385–1.59; α-endosulfan, 0.034–1.25, 0.021–1.22, 0.032–3.62; β-endosulfan, 0.665–1.23,0.008–3.60, 0.005–3.97; endosulfan sulphate, 0.959–1.34, 0.035–3.08, 0.012–1.80; lindane, bdl,0.005–0.82, 1.19–1.56; chlorpyrifos, 0.702–4.06,0.005–1.51, 0.156–7.04; and diazinon, bdl, 0–0.150, 0.001–0.006. At the mouth of the river, whereit discharges into the sea, the levels of almost allthe residues were higher than upstream.

Fate and transport of ethoprophos in the Jamaican environment

The hydrolytic half lives of ethoprophos in distilled, river, brackish and open sea water were 25, 133, 65 and 81 days, respectively. Under laboratory conditions, volatilisation of the residues after 12 h was 1.4-3.6, 2.3-4.5 and 6.5-20.2% from a sandy loam soil with 1, 10 and 20% moisture levels, respectively. Photolysis in soil was significantly faster (P < 0.05) in direct sunlight (T1/2 of 4.7 days) than in the shade (T1/2 of 12.3 days). The microbial degradation of ethoprophos was more than two-fold faster in unsterile soil (T1/2 of 10.9 days) than in sterile soil (T1/2 of 28.8 days). The runoff of ethoprophos from unweeded plantation soil at 23 degrees slope was significantly (P = 0.015) less than at 38 degrees slope; the amounts lost after 9 weeks and 27.5 mm of rainfall were 89.4 and 91.2%, respectively, of the applied amount from the two respective slopes. In the weeded plots, 93.6 and 92.4% of the applied insecticide were lost from 23 degrees and 38 degrees slopes, respectively. Under laboratory conditions, between 67.0 and 85.1% of ethoprophos leached through the soil columns. Under field conditions, after 9 weeks and 25 mm of rainfall, only 2.8 and 2.0% residues were recovered at a depth of 10-15 cm from unweeded and weeded slopes, respectively at 23 degrees slope, and 2.2 and 1.9% from the two respective plots at 38 degrees slope.

Toxicity, Bioaccumulation and Tissue Partitioning of Dieldrin by the Shrimp, Macrobrachium Faustinum de Sassure, in Fresh and Brackish Waters of Jamaica

The 2-week no observed effect (NOEC) and lowest observed effect (LOEC) concentrations of dieldrin were determined for Macrobrachium faustinum de Sassure in fresh and brackish waters. LOEC1, 10, 50, 95 values in fresh water were 0.001, 0.003, 0.011 and 0.058 µg l−1, respectively, and in brackish water, 0.00006, 0.00027, 0.00165, and 0.0172 µg l−1, respectively. The 96-hr LC10, LC50 and LC95 values were 0.029, 0.123 and 0.771 µg l−1, respectively. It is proposed that NOEC and LOEC be redefined to take into account the percentage of individuals affected, the severity of symptoms and the recovery of poisoned individuals. Two new terms are proposed - Median Observable Effect Concentration (MOEC) for pronounced toxic symptoms in most individuals but mortality in <50%, and Pronounced Observed Effect Concentration (POEC), which inflicts mortality in >50% individuals. Bioaccumulation of dieldrin by M. faustinum from surrounding fresh and brackish waters were rapid and fairly uniform for the first 48 h when the bioconcentration equilibrium (14.4 ± 0.42 ng g−1 at 0.001 µg l−1 and 42.5 ± 1.72ng g−1 at 0.01 Φg l−1) was achieved. Relative partitioning of residues (ng g−1 wet wt.), after 24h exposure to 0.001 µg l−1 of dieldrin in fresh water, in the different tissues was hepatopancreas > gonads > gills > large claws > muscle and exoskeleton. Shrimp which had accumulated 10.5 ± 0.52 ng g−1 dieldrin in fresh and brackish water, eliminated only about 52% of the residues after eight days in uncontaminated water.