THE invasion by the armyworm in most farming districts in the country occurs in almost every cropping season.
However, for the BaTonga fighting this pest has been easy as they use natural pesticides and other insects.
The adoption of organic and natural pesticides by the BaTonga farmers was as a result of the lack of fertilisers as the colonial government relegated them to poverty and condemned their rugged terrain as unsuitable for farming.
They were forced to be innovative to save their crops and since then, they have relied on bio -pesticides with excellent results.
The BaTonga people, traditionally living along the Zambezi escarpment, have intimate knowledge of over 600 local medicinal plants with over 100 uses to treat wounds, bites, coughs, diarrheoa to name a few.
They have also used these herbal remedies as bio-pesticides in their gardens and fields and the effects were pleasing as they recorded low crop losses.
This proves that if traditional knowledge systems such as those of the BaTonga are harnessed and used in the conventional set-up this could help to alleviate the pest problem.
The BaTonga farmers who practise zero tillage have found the use of certain weevils and mantis that destroy pests such as locusts and worms.
The insects are caught and kept in well aerated containers before they are unleashed in the fields or gardens to deal with problem pests.
Mixtures of soot, fish droppings and chilli are also prepared and sprayed on vegetables and other plants to protect them from worms and other insects.
This type of farming is practised along the banks of the Zambezi River in small or big community gardens where water is either drawn from shallow wells dug along the banks of the river and used to water the crops.
Further inland conservation farming is practised by digging small holes around the plant, manure (murakwani) is added on the plant.
When it rains, the small holes collect the water which permeates to the roots of the plant.
Wetlands near the rivers are also fully conserved although they are also utilised for farming purposes during the dry season.
Crops such as sweet potatoes, beans and other legumes are planted.
Sugarcane is abundant at certain wetlands.
Wooden hoes carved out of strong mukwa and teak logs are used for the digging.
Most BaTonga farmers cannot afford pesticides hence the reliance and usage of natural pesticides
While there are advantages in the use of pesticides, BaTonga farmers usually do so without taking safety precautions such as protecting oneself against the spray mist, or using the correct dosage and intervals between applications.
This has often resulted in insects developing traits against certain pesticides.
Aggressive marketing strategies by retailers and farmer stores coerce barely literate farmers to sell toxic pesticides of poor quality that are sometimes inappropriate for targeted crops.
This has caused serious health risks to the farmers and the environment.
Acute and chronic side effects include the development of skin and neurological disorders.
While most farmers have ignored the use of natural ways in the management of pests and disease on their crops, bio-pesticides that are derived from plants and macro-organisms such as viruses and fungi that have virtually no adverse impact on the environmental and human health.
Bio-pesticides are produced in Binga with cheap materials and simple equipment and can generate additional household income by engaging women groups or youths.
Bio-pesticides have become the only solution to poor rural and organic horticultural BaTonga farmers as they are as effective as conventional pesticides, although their killing effect is a bit slower.
At the end of the cropping season, the bio-pesticides can still protect crops well, providing the same or better yield as chemical treatments.
The issue of the slow killing effect has no significance especially in the face of climate change where most of the agricultural pests have developed resistance to chemical pesticides.
According to scientists, insects have over the years developed detoxification mechanisms as a result of farmers’ reliance on the same chemical substances.
This is well documented for one common pest -the diamond back moth which is now resistant to almost all commercial pesticides.
However, resistance is not a problem with bio-pesticides and there are no signs so far according to insect ecologists.
They have cited two major reasons for this.
First it was observed that if living organisms are deployed as pesticides against pests, the insect-specific fungus or virus can co-evolve to counter attack if the target organism begins to develop resistance.
The second reason cited was that if the plant extract used in bio- pesticides contains several different active substances, which are more difficult for insects to develop resistance to than the one or two active molecules present in most chemical pesticides.
According to the International Institute of Tropical Agriculture recent examples of the production of a baculovirus to attack the cotton bollworm in India clearly demonstrates the feasibility of bio-pesticides.
The community based production of this virus was initially funded by a grant from the United Kingdom Department for International Development.
The production continued beyond the end of the project, prompting non-governmental organisations, the private sector and governments to set up production units.
While in Zimbabwe some farmers know the advantages of using botanical extracts, such as the absence of hazardous side effects, they are reluctant to invest extra time and labour to produce them by themselves during the peak of the cropping season.
It is imperative for research institutions and farmer organisations and the Agritex to develop appropriate training materials to support the use, production and quality control of bio-pesticides.
Similarly, marketers, consumers and policy makers need to be made aware of the higher quality and safety of products treated with bio-pesticides.
The Zimbabwe Environment Outlook states that although the country boasts of a strict and robust pesticide monitoring analysis system, there is no data on quantity of the persistent toxic substances in the environment.
Relatively high levels of persistent toxic substances have been detected in water, vegetation and animals in Zimbabwe since the 1970s.
These persistent toxic pesticides are being substituted by with biodegradable alternatives, hence the need to promote bio-pesticides.
As a climate mitigation measure, there is need for the ddevelopment and promotion of drought-tolerant and early-maturing crop species, the breeding of drought- and disease-resistant crops, climate forecasting and provision of timely advice to governments, private sector, extension services and farmers.