Agriculturists in some parts of the country are being forced to manually pollinate their crops due to a decline in bee populations. Scientists say the chemicals, meant to kill pests, are also killing bees and other insects that transfer pollen.

Milliam Murigi @millymur1

When you walk into Samuel Nderitu’s farm early in the morning during the flowering period, you will find him busy transferring pollen from male flowers to female flowers by hand.

With a paintbrush and a soft sponge, he moves from one male flower to another brushing the pollen into the sponge.

After collecting enough pollen, he goes around again brushing the pollen onto female flowers, trying to get it onto what’s called the stigma of the flower (female part of the flower).

Other times, he is forced to rub the male part directly on the female part. However, when doing this he is usually extra careful to ensure that the male part touches all parts of the female blossom.

“I have been assisting some of my crops to pollinate for the last 10 years. This is because there has been a drastic reduction in pollinators, especially bees, which in nature pollinates up to 75 per cent of the crops that I grow in this garden,” says the pumpkin farmer. 

Pollinators comprise a diverse group of animals dominated by insects, especially bees, some species of flies, wasps, butterflies, moths, beetles, weevils, ants, midges, bats, birds, primates, marsupials, rodents and reptiles

Bees, including managed honeybees, together with many wild species are the predominant and most economically important group of pollinators in most regions.

This is because more than 90 per cent of the leading global crop types are visited by bees and around 30 per cent by flies, while each of the other taxa visits less than six per cent of the crop types.

Non-selective pesticides

He says use of chemicals, such as pesticides, fungicides, herbicides and nematocides by farmers has been the main contribution to the bee decline.

The reason being these pest killers are non-selective and, therefore, kill everything that they come in contact with.

Also, natural habitat that bees used to live in has mostly gone, and that has affected bees around the world.

“To successfully pollinate your crops by hand, you first need to identify the male and female flowers.

Male flowers are borne straight off the vine while females have a small fruit swelling at the base near the stem.

After that you remove the petals from a male blossom to reveal the stamen at its centre where the pollen is. You then transfer the pollen to the female flower,” he explains. 

All these need to be done early in the morning before the bees become active, because they might carry away the pollen that has been applied on the female part Though this is a tedious process, Nderitu says that it’s worth it, especially for pumpkin farmers. This technique also works for all the Cucurbita family crops, such as squash, cucumber, zucchini and gourds.

Eliud Muli, senior lecturer in Entomology at South Eastern Kenya University says that other than pollination, bees play an important role in ecosystem services, such as sustainable food production, ecosystem stability, habitat conservation, and they give opportunities for income generation.

That is why their decline should not worry us. “Pollination impacts directly on food and nutrition security of the farmer and family.

Sufficiently pollinated crops have higher yields and better quality. Colony losses in the last two decades have raised a lot of concern on food security in the future,” says Muli.

Though it is believed that in Kenya there are about 400 to 500 bee species, Muli says that general information on pollinators is minimal in Kenya and pollination is not considered to be critical in crop production, thus not planned for alongside other production inputs.

“It is believed that close to 35 per cent of invertebrate pollinators (bees and butterflies) face extinction globally.

This can be reversed if we educate and create awareness on strategies that promote pollinator health, such as Integrated Pest Management, which reduces dependence on chemical pesticides,” says Muli.

Produce less food

June Aluoch from Pest Control Product Board, Ecotoxicology and Environmental Safety Division says if we need to have more bees as a country, we need to  restrict the use of chemical pesticides that are toxic to bees in crops that are actively pollinated by invertebrate pollinators, document and replicate best practices in pollinator conservation and resilience, make budgetary allocations in work plans to promote pollinator conservation and resilience activities, and protect heritage sites and ecological farming practices.

“Without insect pollination, about one third of the crops we eat would have to be pollinated by other means, or they would produce significantly less food.

Up to 75 per cent of our crops would suffer some decrease in productivity,” says June.

Nderitu says that famers should be the ones to blame if pollinators disappear.

This is because there are so many alternatives and options that can be used to control pests and diseases rather than using harmful chemicals.

The government, he says  is also to blame for allowing red tape chemicals to be imported in the country.

Some chemicals have been black listed in the west, but they are still being imported and allowed to be used in Kenya. 

Though assisted pollination is a viable solution, Nderitu says that we still need bees because this method faces so many challenges.

One of the challenges is that the male flower lasts only for 24 hours and a farmer needs to be accurate when it comes to timing mature pollen.

Another challenge is that one might transport pathogens from plant to plant during the whole process.

“I would urge farmers to start practicing ecological organic agriculture and agroecology,” urges Nderitu.

To attract more bees to his farm, Nderitu grows diverse plants and food crops that would attract organisms, including flowers that produce yellow petals. Sometimes he brings some honey and honey combs to attract the bees.