Field Investigations on the Interrelationships of the Big-Headed Ant, the Gray Pineapple Mealybug, and Pineapple Mealybug Wilt Disease in Hawaii

The population density of the big-headed ant was higher during the second (ratoon) crop than during the first crop of pineapple at both Poamoho and Molokai. At Poamoho, no mealybug wilt plants were found in plots where ants had been controlled, while the number of such plants increased sharply during the second crop in plots where ants were not controlled. The incidence of mealybug wilt was higher at the edges of plots than toward the middle reflecting the greater abundance of ants and mealybugs on the margins on the plots. Wilt spread in a contagious manner with the number of diseased plants increasing at a logrithmic rate over time. The coefficient of correlation between the number of ants caught in pitfall traps and the percentage of mealybug infested plants was very high (r = 0.97). Infestation of the Molokai experimental planting by big-headed ants started at the edges of plantings adjacent to abandoned fields and waste areas. Invasion progressed slowly, and two and one half years elapsed before all plots had become infested. Ant and mealybug populations in infested plots increased gradually and appeared to be strongly influenced by the phenology of the pineapple plants during the first fruit crop. Unusually heavy rainfall during March and April 1979 may have caused the dramatic reduction in ant populations observed then. Highest ant population levels occured about three years after planting when all untreated plots became nearly uniformly infested. Pest management strategies for pineapple ants and mealybugs are discussed, and it is suggested that a program of ant surveillance using bait stakes, coupled with treatment of field margins and adjacent infested old fields or uncultivated areas when ants are discovered, can prevent migration of these pests into plantation fields

Chimpanzees (Pan troglodytes) navigate to find hidden fruit in a virtual environment

Action Contro

The Organization of Agricultural Research in Western Developed Countries

This paper reviews agricultural research structural and organization changes in western developed countries, examines new financing prospects for agricultural research, and provides some tentative conclusions about which organizations are best positioned to provide services for the 21st century. Giventhat these countries faces many similar economic, political, scientific, andagroclimatic factors and fiscal issues, we canexpect a similar set of similar new developments thathave potentially important and widespread long-run implications. After three common developments are outlined, principles ofimpure public good financing are applied leading to the following agricultural science policy recommendations (i) new political jurisdictions should be formed to finance research, e.g., new alliances across countries and subregions within large countries, (ii) intellecmal property rights should be strengthened to increase the total amount and share oftotal (public and private) agricultural research that is privately financed and conducted, i.e., the private sector should find it profitable to undertake a large share ofapplied research but not be expected to finance public sector agriculmral research, (iii) the public sector should redirect its research efforts increasingly to areas that are socially worthwhile but not privately undertaken, e.g.,in the basic and pretechnology areas, on envkonmental, resources, food safety and human nutrition, and policy. Finally, large countries that have developed asystem ofshared public and private financmg and performance and decentralized public support ofagricultural research seem best position for meeting the needs ofthe 21st centur