Parasitic predator preys on pink mealybugs

The island of Grenada has suffered rapidly mounting levels of damage to its agricultural and horticultural production since the arrival of the pink mealybug (PMB) in 1993. The pest, Maconellicoccus hirsutus, is found in many other parts of the world but is a newcomer to the Caribbean, where it has had a particularly damaging effect on a large number of trees, ornamental shrubs, fruits and vegetables. As a result of this invasion, Grenada's horticultural production has been severely affected in quantity and quality, with exports being rejected by other Caribbean countries. In early 1995 the mealybug found its way to neighbouring Trinidad and has now been confirmed in St. Kitts. Applying selective pesticides and burning affected materials only offers a short-term solution, so a sustainable control programme has been launched to introduce natural enemies of the mealybug from its native range. The International Institute of Biological Control (IIBC), supported by FAO and in collaboration with Caribbean ministry colleagues, has been studying mealybug control methods elsewhere, in order to come up with a suitable natural enemy to reduce mealybug populations. The parasitic wasp Anagyrus kamali was recorded as parasitizing 66-98% of PMB in the field: it shows a strong preference for mealybugs in general, and PMB in particular. Female wasps lay their eggs inside the host insect and the wasp larva develops internally, killing its host in the process. Live wasps were hand-carried to Grenada in October 1995, and are currently being multiplied in an insectary on established mealybug cultures. Staff of the Ministry of Agriculture in Grenada are being trained in rearing methods and they made the first pilot field release of 1,000 adults last November. They will now monitor how the wasp adapts to the environmental conditions in Grenada, make further releases and assess its impact on PMB populations. Successful biocontrol of mealybugs in Africa has resulted in massive savings to farmers; in Togo alone mango growers saved $2 million in lost production. Controlling PMB in Grenada will directly benefit more than 8,000 farmers and, indirectly, all those involved in agriculture, the island's largest employer and foreign exchange earner. As part of its wider aims in the Caribbean, the programme is also training farmers and agricultural industries in how to integrate biological control into their cropping systems and reduce their reliance on chemical methods. D J Girling Information Officer llBC Silwood Park, Buckhurst Road Ascot, Berks SL5 7TA UKThe island of Grenada has suffered rapidly mounting levels of damage to its agricultural and horticultural production since the arrival of the pink mealybug (PMB) in 1993. The pest, Maconellicoccus hirsutus, is found in many other parts of the..