435
5.3 Introduction and Rearing of Oecophylla longinoda
Colonies
Experiments were conducted in already established cashew trees of variety AC4
aged 12 years and planted at spacing of 12 m by 12 m at Naliendele Agricultural
Research Institute in Tanzania. Harvested nests for each colony were introduced
into the canopy of experimental cashew trees following the already established
experimental design. Trees introduced with members of the same colony were connected with Manila ropes to aid movements of the weaver ants among trees for
increased patrol to protect the target plants (Peng et al. 2010). Generally, using
O. longinoda as biocontrol agents requires a simple ten-step protocol summarized below:
1. Identifying colony source.
2. Mapping the colonies and marking boundaries for each colony.
3. Identifying the queen nest.
4. Harvesting the nests and separating colonies. Queen nest must be harvested
first.
5. Packaging the harvested nests in perforated or aerated bags and tying them to
avoid escape.
6. Carefully transporting nests to the target farm area. Transportation time should
not exceed 3 hours.
7. Preparing the field to which new release is intended. This would in a sequence
come in as step number 2, but it is included at this stage for convenience.
8. Locating the right recipient tree and opening loose the containing bags to
release the ants.
9. Post-release care, which includes protection from enemies, and supplementary
feeding.
10. Promotion for further establishment, patrol of the trees by aid of ropes for pest
control and networking among members of the same colony as well as maintaining colony separators.
In the current experiment, a randomized complete block design (RCBD) was
used with three control options as treatments, namely, (1) use of O. longinoda, (2)
use of recommended insecticides and (3) control (where nothing was applied). The
experiments were replicated four times. Each experimental unit covered 96 cashew
trees with the total experimental areas with 384 trees. After introduction, O. longinoda were supplied with ground fish protein and sugar until colonies were well
established and ready to patrol the cashew (Abdulla 2016). The recommended
insecticide, Karate
®
(50 g/L of Lambda cyhalothrin), was sprayed on cashew trees
after every 2 weeks at the recommended rate of 5 mL/L per tree (NARI 2010), during the active growth of cashew using a motorized backpack sprayer (M 225–20
Motor-Rückensprühgerät). Sulphur (falcon dust) was also prophylactically sprayed
at a rate of 250 g/tree at flowering period, supplemented with systemic fungicide,
Bayfidan (triadimenol 250 g/L), to control powdery mildew disease (PMD; Oidium
Economic Rationale of Using African Weaver Ants, Oecophylla longinoda…
5.3 Introduction and Rearing of Oecophylla longinoda
Colonies
Experiments were conducted in already established cashew trees of variety AC4
aged 12 years and planted at spacing of 12 m by 12 m at Naliendele Agricultural
Research Institute in Tanzania. Harvested nests for each colony were introduced
into the canopy of experimental cashew trees following the already established
experimental design. Trees introduced with members of the same colony were connected with Manila ropes to aid movements of the weaver ants among trees for
increased patrol to protect the target plants (Peng et al. 2010). Generally, using
O. longinoda as biocontrol agents requires a simple ten-step protocol summarized below:
1. Identifying colony source.
2. Mapping the colonies and marking boundaries for each colony.
3. Identifying the queen nest.
4. Harvesting the nests and separating colonies. Queen nest must be harvested
first.
5. Packaging the harvested nests in perforated or aerated bags and tying them to
avoid escape.
6. Carefully transporting nests to the target farm area. Transportation time should
not exceed 3 hours.
7. Preparing the field to which new release is intended. This would in a sequence
come in as step number 2, but it is included at this stage for convenience.
8. Locating the right recipient tree and opening loose the containing bags to
release the ants.
9. Post-release care, which includes protection from enemies, and supplementary
feeding.
10. Promotion for further establishment, patrol of the trees by aid of ropes for pest
control and networking among members of the same colony as well as maintaining colony separators.
In the current experiment, a randomized complete block design (RCBD) was
used with three control options as treatments, namely, (1) use of O. longinoda, (2)
use of recommended insecticides and (3) control (where nothing was applied). The
experiments were replicated four times. Each experimental unit covered 96 cashew
trees with the total experimental areas with 384 trees. After introduction, O. longinoda were supplied with ground fish protein and sugar until colonies were well
established and ready to patrol the cashew (Abdulla 2016). The recommended
insecticide, Karate
®
(50 g/L of Lambda cyhalothrin), was sprayed on cashew trees
after every 2 weeks at the recommended rate of 5 mL/L per tree (NARI 2010), during the active growth of cashew using a motorized backpack sprayer (M 225–20
Motor-Rückensprühgerät). Sulphur (falcon dust) was also prophylactically sprayed
at a rate of 250 g/tree at flowering period, supplemented with systemic fungicide,
Bayfidan (triadimenol 250 g/L), to control powdery mildew disease (PMD; Oidium
Economic Rationale of Using African Weaver Ants, Oecophylla longinoda…