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Economic Rationale of Using African Weaver Ants, Oecophylla longinoda Latreille (Hymenoptera: Formicidae) for Sustainable Management of Cashew Pests in Tanzania

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Abstract

Cashew nut, Anacardium occidentale Linnaeus, is an important crop to the African economy, contributing to livelihood of many families. It is among the top foreign-currency-earning crops in East and West African countries. The crop is attacked by several sucking pests that survive on multiple host plants. These include: Pseudotheraptus wayi, Helopeltis anacardii, H. schoutedeni, and Selenothrips rubrocinctus. Management of these pests is usually a challenge which triggers irrational use of synthetic pesticides. Excessive use of pesticides concerns human health and pollution in the environment. The use of African weaver ants, Oecophylla longinoda, has presented an alternative to pesticides for sustainable cashew pest management. The predator was found to be as highly effective (P < 0.0001) as the recommended insecticide (Lambda cyhalothrin) (P < 0.0001) in controlling cashew pests. The several economic analyses on the profitability of the technology over the recommended pesticides by partial budgeting, marginal rate of returns, benefit-cost ratio and net present value proved O. longionda to be superior to pesticides. The partial budgeting indicated a net benefit of US$7.72 per cashew tree by changing from insecticides to O. longinoda within two seasons. 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.

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... The present study exposed the erceness of major workers foragers encounter with any intruders and other weaver ants from different colonies, showing that foraging and colony defense is a risky duty, impairing substantially the survival ability and therefore incurring high mortality rates in ants (Chapuisat & Keller, 2002). This is particularly true in the Oecophylla genus, where major workers aggressively defend extensive territories, by performing permanent foraging duties, against con-speci c individuals from different colonies seen as competitors or intruders in the case of O. smaragdina (Peng et al., 1999;Saarinen, 2006;Peng & Christian, 2009) and O. longinoda (Rwegasira et al., 2020). The same strategy is systematically adopted as soon as the colony expands its territory by performing initially extensive foraging activity to explore suitable new areas (Hölldobler & Wilson, 1990). ...
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Asian weaver ant, Oecophylla smaradigma is a nuisance species, effect the plantation employee due to their painful bites. The O. smaragdina was reported as one of the potential predators for the invasive bagworm species, Pteroma pendula in the oil palm plantation. Despite their important role in the plantation, however the study on the ecology and behaviour of the O. smaragdina is still lacking and not discovered. The objectives of this study were to investigate the relationships between the foraging daily activities of the O. smaragdina with the weather parameters. In 2018-2022, this study investigates the trunk foraging activity pattern of O. smaragdina colonies (9 days per colony) from selected plantations, as an effort of mitigation. In 2020-2022, a targeted field study was undertaken to examine the daily trunk foraging activities of major workers in relation to air temperature (AT), relative humidity (RH), air pressure (AP) and rainfall (RI). Ground forager behaviours were observed and examined from the trunk trail split covering an average frontal fluctuating angle from base palms. It is suggested that O. smaragdina is a diurnal ant species with much lesser crepuscular intensity. It is demonstrating similar daily foraging activity patterns featuring higher intensity during the warmest daily periods in relation to population size relative abundance. This was irrespective of the dry-wet seasons corresponding to low activity from late scotophase to early photophase, exhibiting a bimodal foraging pattern. Throughout the overnight period, foraging activity ceased. O. smaragdina is a visual light dependent hunter for efficient intensive foraging. Active foragers reached peaks at around 1100 to 1530 hours, and from 1745 to 1845 hours. Between 1620 and 1650 hours, foragers demonstrated a two-fold daily decline in intensity on average. There was a strong positive correlation between foraging activity, AT and AP but negatively correlated with RH. Sustained RI stopped the trunk-ground trail activity of O. smaragdina, exposing outbound foragers withdrawing massively to the canopies. Defensive territorial layers are established from the base palm trunks reaching an average 5 m distance featuring two distinct spatial arrangements. Major workers trunk trails split into several new lines on an average 3 m radius showing higher foraging density. The trails broke off to expand into a web shape figure occupation reaching on average 5 m. The avoidance of forager relentless attacks can be achieved during the daily low activity periods (before 1000 hours) for pruning and harvesting tasks if the adoption of O. smaragdina is implemented to control the invasive Metisa plana bagworm species.
... In Zanzibar, O. longinoda was reported attending Saissetia zanzibarensis (Way, 1954), as was observed in this study. The ant has also been found in close association with other mealybugs and scale insects (Dwomoh et al., 2008;Olotu et al., 2013); it is used as a biological control agent against other, non-scale pests' elsewhere (Way, 1954;Mele et al., 2007;Olotu et al., 2013;Carrillo et al., 2017;Rwegasira et al., 2020). ...
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Cashew (Anacardium occidentale L.) is the fourth most valuable Tanzanian export crop after coffee, cotton and tea. Following a steady increase in production from the middle of this century, there was a dramatic decline from 145,000 t in 1973 to 16,500 t in 1986. This was caused by a complex of socio-economic (low producer prices, inefficient marketing, villagisation) and biological factors (cashew powdery mildew disease, low tree yields, overcrowding of trees). Recently, higher cashew prices and liberalised marketing have created favourable conditions that have encouraged farmers to tackle several of the biological constraints on production. As a result, cashew production has risen steadily from 16,500 t in 1986 to 70,320 t in 1994.
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The present study has been formulated to study the cost of cultivation of stevia to encourage the farmer regarding cultivation of this plant and also provide information regarding profitability of cultivation. Stevia become a potential and renewable raw material in the food market because the increase in the number of diabetic and health conscious individual boost up the international market of high quality stevia leaves which is a non-caloric natural sugar. Lack of information regarding the cost of cultivation of stevia specially in Indian context generate plenty of confusion with regard to cultivation of this plant and also about selection of the profitable propagating material. The present study thus concerned with calculating the cost of cultivation, return and cost benefit ratio to identify economic viability and technical feasibility of stevia cultivation through cutting and tissue culture propagated planting material. For this an experimental plot size of 100x100 m each was used for cultivation for 3 years with cutting and tissue cultured plantlets as propagating material. The cost of cultivation refers to the total expenses incurred in cultivating stevia, expressed on a per hectare basis and worked out using operation wise approach in both the cases for three years. Lastly benefit cost ratio was incurred which is the ratio of the present worth of gross costs and represents the economic viability of the two projects. From the two project it was revealed that fixed as well as variable cost was more in tissue culture plantlets propagated field but tissue cultured plants favour disease free clean cultivation with high foliage production as compared with cutting where disease and pest infection was severe. For this during three years of economic life total sales of dry stevia leaves was generate more income in tissue cultured propagule established fields than cutting propagated field. From the cost benefit ratio of the two projects it was clear that profit of the two projects was comparable with each other and was technically feasible and economically viable.
Article
The beneficial effects of ants in agriculture and forestry have already been reviewed in Chapter 11. In the following pages I discuss the methods by which ants have been utilized in crops to limit maladies and highlight the strengths and weaknesses of the various approaches. Arising from this review a checklist of points to consider when promoting beneficial is presented so that future ant manipulation attempts can draw on these experiences. This account distinguishes between species that are physically "introduced" into an area from outside and resident species that are "encouraged" to spread their range or utilize an enemy species more effectively. The term "promoted" collectively refers to both methods.
Article
Cashew (Anacardium occidentale L.) has become a very important non-traditional tree crop in Ghana. The crop is, however, attacked by sap-sucking insects, particularly the mosquito bug, Helopeltis schoutedeni Reuter, the leaf-footed bug, Pseudotheraptus devastans (Dist.), and the coreid bug, Anoplocnemis curvipes (F.), which feed on shoots, panicles and fruits. Their damage is characterised by withering of the latter. In Ghana, Oecophylla longinoda Latr. occurs in large numbers on cashew and other native plants, but little is known about its relationship with insect pests. The relationship between O. longinoda and shoot and panicle damage by sap-sucking bugs and the effectiveness of O. longinoda as a biocontrol agent in the protection of cashew as compared with two chemical insecticides, lambda-cyhalothrin (Karate) and cypermethrin + dimethoate (Cyperdim), were therefore investigated at Bole in the northern region of Ghana. There was a negative correlation between numbers of O. longinoda nests and pest damage. Trees treated with cypermethrin + dimethoate (969 mg AI mL(-1) tree(-1)) and lambda-cyhalothrin (100 mg AI mL(-1) tree(-1)) recorded the smallest bug numbers, followed by O. longinoda. Trees infested by Oecophylla longinoda and trees treated with cypermethrin + dimethoate and with lambda-cyhalothrin had less than 6% pest damage to shoots, panicles and fruits, while water-sprayed trees recorded damage as high as 36.8% (shoots) in February, 32.9% (panicles) in February and 37.8% (fruits) in March. Cypermethrin + dimethoate again recorded the highest (485.0 kg ha(-1)) nut yield, followed by O. longinoda (431.0 kg ha(-1)), with water recording the lowest (93.0 kg ha(-1)) nut yield. The results indicate that O. longinoda can be used to control some sucking bugs as effectively as some insecticides.
Weaver ant, Oecophylla longinoda Latreille (Hymenoptera: Formicidae) as biocontrol agent on major insect pests of cashew and mango in Tanzania
  • N R Abdulla
A study of the weaver ant
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A masterpiece evolution-Oecophylla weaver ants (Hymenoptera: Formicidae)
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Cashew nuts and production development in Nigeria. Am -Euras
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Deutsche Gesellschaft für Internationale Zusammenarbeit GmbH and The Advisory Service on Agricultural Research for Development
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Utilizing economically beneficial ants. In: Bradleigh S (ed) Economic impact and control of social insects
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Insect pests of cashew and their management
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Integrated cashew improvement program using weaver ants as a major component - photo book for cashew growers in Vietnam
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Definition of Marginal Rate of Return
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Compendium of lectures delivered during the Advanced Training Course on “Novel Approaches in Pest and Pesticide Management in Agro-Ecosystem”
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Partial budgeting: a tool to analyze farm business changes
  • R Tigner
Economic Value of Using African Weaver Ants as Biological Control in Fruit Production and Export in Tanzania
  • J G William
Partial budgeting analysis of different strategies for management of insect pests in cashew and mango orchards in Tanzania
  • J G William
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A guide to IPM in mango production in Kenya
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Survey of insect species associated with cashew
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The effectiveness of using weaver ant biocontrol in Southern Asian citrus and mango
  • J Offenberg
  • T B Nguyen
  • D Wiwatwitaya
An economic analysis of Stevia
  • Amb Das
  • M Mandal