Pest Management in Miombo Fruit Trees - Indigenous Fruit Trees in the Tropics: Domestication, Utilization and Commercialization - page 385

pests as well as in their suitability to the intended site. In the current
domestication programme there is no clear strategy to explicitly include pest
resistance during selection or germplasm propagation. The inclusion of farmers'
criteria for selection may unintentionally include selection for pest resistance,
since farmers are unlikely to select individual trees known to suffer severe
attack. Leakey (1999) suggests that while selection for superior yielding
agroforestry trees continues, breeding should now focus on criteria such as pest
resistance and product quality rather than yield.
Chemical control
Chemical control is an integral component of on-farm pest management, and a
variety of chemicals may be needed. However, chemical pesticides should be
used only: (i) in combination with other IPM practices, where other practices
have failed to produce satisfactory results; or (ii) in situations where IPM
practices are not available. Special precautions are warranted when prescribing
'protective' chemical control. Insecticides can be used in a selective way. Two
environmentally benign insecticide bait technologies developed for fruit fly and
false codling moth control are described below. The insecticide bait technology
for the management of fruit flies (Lux et al ., 1998) involves a combination of
food bait and insecticide to attract and kill adult fruit flies of various species.
The poison bait consists of a mixture of insecticides, lure (protein hydrolysate
or yeast product) and water. The poison bait is applied to approximately 1 m 2
of foliage area per tree in such a way that fruits on the tree are not hit by the
insecticide drift. It is not necessary to wet the whole tree; a section on one side
of the tree will be adequate.
LastCall TM (IPM Tech, 2002), an insecticide bait used for the control of the
false codling moth, is a special paste containing a standard insecticide, a
pheromone and ultraviolet protection, all in a custom-designed dispenser. The
preferred insecticide is permethrin, although several other insecticides work just
as effectively. The product is packed in a special dispenser that contains 150 g
of material, enough for approximately 2.5 acres (1 ha). In high-density apple
orchards, one or two droplets of LastCall are applied to the trunk or branches
of each apple tree. The male codling moth is attracted to the pheromone in
LastCall and attempts to mate with the product. The moth is killed shortly after
making contact with the insecticide. This will result in only unfertilized female
moths in the population, which are unable to lay viable eggs in the fruit.
Compared with conventional pesticide sprays, LastCall delivers a minute
amount of pesticide.
20.5.2 Postharvest pest management and quality control
Postharvest treatments of fruits involve cleaning to remove dirt, dipping of fruit
in cold water to remove field heat, dipping in hot water (not exceeding 55°C for
5 min) and treatment with fungicides and insecticides. Other chemical
compounds, such as antioxidants and growth regulators, are also applied to