430
The dominance analysis for marginal rate of returns indicated a net profit of
US$11.39 per tree in two seasons compared to US$5.74 per tree gained from
Lambda cyhalothrin. If adopted for use, the predator will provide a sustainable
solution to cashew pest management and overcome the pesticide residue threats in
marketed cashew from Africa.
1 Introduction
Management of cashew pests, wherever cashew nut is grown, has been a long-term
challenge due to the perennial nature of the crop that ensures continued availability
of the host plant, season after seasons. In addition, most of the notorious cashew
pests are known to survive in multiple host plants which sustain their continued
existence and subsequent reoccurrence on cashew plants whenever the suitable
plant parts such as tender growing leaves, flower buds, inflorescences, fruits and
nuts become available. Cashew nut growers in Africa rely heavily on pesticides
(Martin et al. 1997; NARI 2010) whose advantages in controlling pests leave a lot
of undesirable effects to human, the rest of fauna in agroecosystems and the environment. The limited knowledge on pesticide science and application among farmers in Africa further compounds the problems associated with pesticide use
(Dwomoh et al. 2009). The farmers tend to use the same insecticide season after
season provided it has proven to work, without worrying about the potential development of resistance by the target pest. In Tanzania, one of the major cashewproducing countries in sub-Saharan Africa (SSA), the use of Lambda cyhalothrin
(Karate
®
) has been on preference by most farmers for more than a decade. Non-use
of protective devices, poor dosages, wrong timing of application and poor handling
of insecticides after use aggravate the negative effect of insecticides to farmers’
health and the environment. Accidental or intentional poisoning is not uncommon
among cashew growers in Africa. Insecticide abuse in cashew nut production has
for long been a part and parcel of common practices, such that consumers in export
markets have continuously called for safer products produced through organic
farming. Developing methods for sustainable pest control that would provide alternatives to the chemical control of cashew pest would not only ensure healthy safety
among consumers, it would but also provide protection to growers and the environment. The use of African weaver ants, Oecophylla longinoda Latreille
(Hymenoptera: Formicidae), has for a long time been recommended for sustainable
management of cashew pests, but knowledge on effective exploitation of the biocontrol agent was lacking. The comparative effectiveness of O. longinoda against
commonly used insecticides has never been explored. The objectives of the current
study were (i) to determine the comparative effectiveness of O. longinoda against
major cashew pests and (ii) to undertake economic analyses of the O. longinodabased management to quantify the economic rationale of using the biocontrol agent
as an alternative to recommended insecticides. In the present report, O. longinoda
has proven very effective against major cashew pests and promises a great breakG. M. Rwegasira et al.
The dominance analysis for marginal rate of returns indicated a net profit of
US$11.39 per tree in two seasons compared to US$5.74 per tree gained from
Lambda cyhalothrin. If adopted for use, the predator will provide a sustainable
solution to cashew pest management and overcome the pesticide residue threats in
marketed cashew from Africa.
1 Introduction
Management of cashew pests, wherever cashew nut is grown, has been a long-term
challenge due to the perennial nature of the crop that ensures continued availability
of the host plant, season after seasons. In addition, most of the notorious cashew
pests are known to survive in multiple host plants which sustain their continued
existence and subsequent reoccurrence on cashew plants whenever the suitable
plant parts such as tender growing leaves, flower buds, inflorescences, fruits and
nuts become available. Cashew nut growers in Africa rely heavily on pesticides
(Martin et al. 1997; NARI 2010) whose advantages in controlling pests leave a lot
of undesirable effects to human, the rest of fauna in agroecosystems and the environment. The limited knowledge on pesticide science and application among farmers in Africa further compounds the problems associated with pesticide use
(Dwomoh et al. 2009). The farmers tend to use the same insecticide season after
season provided it has proven to work, without worrying about the potential development of resistance by the target pest. In Tanzania, one of the major cashewproducing countries in sub-Saharan Africa (SSA), the use of Lambda cyhalothrin
(Karate
®
) has been on preference by most farmers for more than a decade. Non-use
of protective devices, poor dosages, wrong timing of application and poor handling
of insecticides after use aggravate the negative effect of insecticides to farmers’
health and the environment. Accidental or intentional poisoning is not uncommon
among cashew growers in Africa. Insecticide abuse in cashew nut production has
for long been a part and parcel of common practices, such that consumers in export
markets have continuously called for safer products produced through organic
farming. Developing methods for sustainable pest control that would provide alternatives to the chemical control of cashew pest would not only ensure healthy safety
among consumers, it would but also provide protection to growers and the environment. The use of African weaver ants, Oecophylla longinoda Latreille
(Hymenoptera: Formicidae), has for a long time been recommended for sustainable
management of cashew pests, but knowledge on effective exploitation of the biocontrol agent was lacking. The comparative effectiveness of O. longinoda against
commonly used insecticides has never been explored. The objectives of the current
study were (i) to determine the comparative effectiveness of O. longinoda against
major cashew pests and (ii) to undertake economic analyses of the O. longinodabased management to quantify the economic rationale of using the biocontrol agent
as an alternative to recommended insecticides. In the present report, O. longinoda
has proven very effective against major cashew pests and promises a great breakG. M. Rwegasira et al.