Pests

: 14 October 2020; Hits: 3149

Institute pioneers banana paper use in managing potato cyst nematodes

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By George Munene

Using artificial and natural nematicides smallholder farmers in Kenya can control the potato cyst nematodes (PCN), a pest that causes yield losses by at least 80 per cent.

In a study of 20 potato growing counties in Kenya Potato Cyst Nematodes (PCNs) were obtained in 71.8 per cent of the counties with Nyandarua County at 47.6 per cent recording the highest PCN field-incidence.The situation is further compounded by the fact the Shangi potato variety grown by 65 per cent of farmers for its shorter dormancy and cooking time is the most susceptible to PCN.

Potatoes are the second most consumed food crop after maize in Kenya, however, production has been on the decline: on a landmass size of 133,532 hectares, the country produced 1.9 million tonnes of potatoes in 2015. Over a corresponding period in 2017 however, Kenya's potato production fell to 1.5 million tonnes off 192,341 hectares.

With Nyandarua being the country's potato basket, accounting for up to 40 per cent of the total production of potatoes, farmers in the county now produce 18 bags, from ¼ acre, down from the previous 30 bags.

PCN, first reported in Kenya in 2015, is classified by KEPHIS as a quarantine pest (a pest subject to official control and regulation due to the potential economic devastation it may present to an area) can lie dormant in soils for up to 20 years and infects 82 per cent of potatoes grown across 22 counties.

Potato plants affected by the PCN exhibit the following characteristics:

leaf discoloration/yellowing and wilting
root with cysts
uneven tuber sizes on one potato plant
reduction in the number of roots
dwarfing of potato tubers and the plant and,
reduction in the number of crops

The nematodes causing PCN are microscopic worms, measuring less than one millimeter in size, meaning they are only visible through a microscope lens. As these symptoms closely mimic water and nutrient deficiency in potatoes, farmers are often left none the wiser on what is causing a reduction in yields.

Potato cyst nematodes are spread by:

Importation of infected plants or plant materials and
locally, by the spread of cysts through soil, wind, water and vehicles

The total production of basic potato seeds in Kenya stands at 6,700 metric tonnes, short of the 30,000 metric tonnes required. According to KEPHIS, the informal sector in Kenya accounts for about 70 per cent of potato seeds propagated by farmers across the country, this makes the curbing of PCN almost impossible.

The easiest way of controlling potato cyst nematodes is the use of nematicides, which are chemical pesticides used to kill plant-parasitic nematodes. Most nematicides are however burned for being toxic to the environment.

Nematicides sold in Kenya include:

NEMATHORIN® 150EC
Adventure® 0.5% GR
Alonze® 50EC
Farmchance® 250 EC

Studies done in Kenya by scientists from The International Institute of Tropical Agriculture have found that covering potato planting seeds with banana paper laced with minimal doses of pesticides during planting deters PCN’s from reaching the potato seeds.

In studies by the University of Florida Food and Agricultural Sciences Extension department cropping in Marigold flowers into potatoes/cabbages has also been scientifically proven to reduce nematode attacks as they act as an alternative host for the nematodes, but produce natural compounds that act as nematicides. This kills the nematodes preventing them from breeding. In time, the nematode population slowly decreases.

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: 31 August 2020; Hits: 3246

Misdiagnosis is a perilous basis for banning crop protection, as Europe proves for us all

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By Eric Kimunguyi

There is a device being used rather often lately by our most vocal lobbyists as they chase new regulation or the overturning of old rules: ‘Europe’ has banned it, or done it, or changed it, they are telling us, as a reason to reshape our own policies.

However, the problem with this form of case building, just as when our children tell us their friend’s parents allow it or have bought it, is that the comparison comes without circumstantial detail, and with the possibility of being untrue in the way it is presented, or, at the very least, of being irrelevant to our own circumstances.

Indeed, few things are more illustrative of those pitfalls than the oft-cited banning of pesticides by Europe. In the ‘one-story-fits-all’ line of case-building, we are told that Europe has banned a mass of pesticides because they are giving humans cancer and reproductive problems. This is painful for experts to witness. For, in our era of short-form information, few non-experts will go and find out the actual truth of what Europe has banned, or why, and what the consequences are. Yet, without that knowledge, we stand in danger of being badly manipulated.

A perfect example is a group of pesticides called neonicotinoids, which are now banned in Europe for outdoor uses: the first point is that they were banned because of their claimed impact on bees, not humans.

For, over a decade ago, the managers of large bee colonies in the US and Europe began reporting bees were simply disappearing. That is worrying for everyone, because bees are key pollinators for many fruits and foods, estimated at around $20bn worth of crops worldwide.

Green lobbyists immediately leapt to the podium calling out pesticides as the cause. There was no scientific evidence that they were, but political pressure anyway began building to ban the class of pesticides called neonicotinoids as harmful to bees – and Europe did.

The US did not, with its Environmental Protection Agency stating there was no scientific evidence to support such a ban. But Europe has moved on a number of issues in recent years without the same need for scientific evidence that the US EPA applies.

However, it turned out it wasn’t pesticides that were emptying the world’s bee hives, but a tiny parasite, the Varroa Destructor mite, which had swept through the European honey bees cultivated in Europe and in the USA, eating bees’ live tissue and infecting them with 13 different viruses, one of which, in particular, saw their wings malform, and made them unable to navigate back to their hives.

Related News:Safe and Effective Use of Pesticides

Information on the bee disease is still growing, but in January, the US National Institutes of Health announced a breakthrough in engineering a bacteria that could protect the bees from it by triggering an immune reaction to this Deformed Wing Virus (DWV). For it is this secondary virus causing the harm, rather than the bees losing a small amount of tissue to the mite – just as malaria catches us as humans, not the tissue we lose to a bite by a mosquito.

Now these are facts, and vital ones, as the world chases a solution to this bee disease.

For in the two years since the EU’s neonicotinoids ban, the Varroa mite has continued infecting Europe’s bees and, with its bee numbers falling faster than ever, it has announced a raft of special assistance for its bee industry in the 2020 agricultural programme. But it also has a new problem in huge, extra crop losses previously prevented by the neonicotinoids. As a result, France this month announced an exception to the neonicotinoids ban for its sugar beet producers, who the Agriculture Minister said, are facing ‘an unprecedented crisis’ as a result of ending their crop protection.

Indeed, the French announcement follows so many ‘derogations’ by member states on this particular ban – which is where they ask to be allowed to set aside a law – that it has become a controversy in its own right in the EU how many ‘derogations’ can be allowed on any ban.

And that is how information starts to look, once the full context is given.

For campaigners who comment on how it is a disgrace we have crop protection in Kenya that is banned in Europe, mean, among other things: we should adopt a ban that there is, definitively, no scientific evidence for, that the US has rejected, that the EU states are resisting and overturning, and which is generating huge crop losses, just because that’s the path the EU took to address the devastation that is actually being caused, primarily, by the Varroa mite.

Of course, it looks a bit different put that way – as ‘disgraceful Kenyan regulations and regulators’ go. Actually, what it looks like, which is the reality, is that our regulators, just like the EPA, are taking a lot of flak, but doing just one thing – sticking with the facts. They aren’t trying to poison Kenyans, and they are keeping a very, very close eye on bees too.

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: 27 August 2020; Hits: 2947

Kenya’s deadliest goat disease costing nearly Sh1/4m per 100 goats in Turkana

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By George Munene

Contagious Caprine Pleuropneumonia (CCPP), a highly infectious disease of the respiratory tract, is the deadliest goat disease in arid and semi-arid regions, costing pastoralists millions of shillings over years and affecting goats throughout Kenya.

The annual costs of CCP in the arid regions is extremely high, with most goats in Kenya in the hands of pastoralists. One study of the economic impact of CCPP on a monitored herd of 100 goats in Turkana County counted the losses as Sh219,132 in just that one herd in a year. (https://onlinelibrary.wiley.com/doi/abs/10.1111/tbed.13317)

With a mortality of 94 per cent if left untreated, medical treatment of the disease is available. But even after treatment, at least half of goats still succumb to it, said Fulgence Mwarongo, the Voi sub county veterinary officer. Moreover, its complete elimination from a herd is difficult and treated animals can still be potential carriers of the disease.

Vaccinating goats at least once every year is the only sure way to protect them from CCPP, he said.

Although goats are its primary host, on rare occasion it also affects sheep, in flocks and herds where they are mixed in with goats. However, CCPP cannot be transmitted to human beings.

It is transmitted by the Mycoplasma F38 and Mycoplasma mycoides capri bacteria.

Mcharo Mbogho a galla goat farmer in Taita Taveta has borne its effects first-hand having lost close to 200 goats to the disease in 2017 when his herd came into contact with a neighbour’s infected goats. The disease causes death within one to three weeks after infection, but can be prevented.

Symptoms

Breathing difficulties/ choked breathing
Weakness and lethargy
Coughing
Foamy discharge from the nose
Loss of appetite, goats will not even drink water
Long stringy saliva
Lungs become edematous (swollen)

Prevention

Bi annual vaccinations against CCPP
Quarantining infected animals
Incubate new goats for at least six to ten days and vaccinate them before introducing them to your herd
If you are able, fence off your grazing area to avoid your goats coming into contact with others
Slaughter infected or exposed animals
Have a clean shed and disinfect it regularly
Do not overpopulate goats in a small area

Related News:How to import breeding goats into Kenya

Treatment