Obert Chifamba Agri-Insight
There is nothing worse than fall armyworm (Spodoptera frugiperda) in cocoon stage and pupating in dry maize cobs, crop residues or in pastures of thick grasses such as Star and Bana.
I remember the anxiety that gripped the country when the Department of Plant Protection and Research Institute chief entomologist, Dr Godfrey Chikwenhere confirmed that fall armyworm had infested most parts of the country.
The pest had been positively identified in some irrigated maize in some parts of such as Manicaland, Bubi, Matabeleland South and Tsholotsho, Matabeleland North.
Though the damage levels were low – ranging from 1 to 5 percent with the crop managing to recover in most cases – just the presence of the pest was enough to get people worried.
In areas such as Umguza and Tsholotsho overlapping generations of up to four cycles were observed and while registered Carbaryl 85 percent Wettable Powder was effective in Masvingo and Lupane achieving up to 100 percent control of the pest, in other parts of the country it failed to effectively control it.
For the effective fight against the pest in Raffingora, Mashonaland West, chemicals such as Lampda, Carbaryl and Fernkill were used either in mixtures or as sole applications.
If left uncontrolled, fall armyworms can destroy a pasture or field of crops in a very short time.
While fall armyworms can damage plants in nearly all stages of development, they usually concentrate on later plantings that have not yet silked.
They can only be effectively controlled while the larvae are small. Early detection and proper timing of an insecticide application are therefore critical.
Control needs to be considered when egg masses are present on 5 percent of the plants or when 25 percent of the plants show damage symptoms and live larvae are still present.
Controlling larger larvae, typically after they are hidden under crop parts will be much more difficult.
Treatments must be applied before larvae burrow deep into the spiral or enter ears of more mature plants
It is exciting to note that fall armyworm samples were extracted to be cultured under laboratory conditions at Mazowe Plant Quarantine and Harare Plant Protection laboratories while the department of research also collected imported maize samples from GMB depots in Matabeleland North Province and Concession Depot to culture them at Plant Quarantine laboratories in Mazowe.
This is a sign of planning ahead of time. Fall armyworm was also observed to attack cobs from milk stage to mature cobs and the fact that it can attack about 80 species of crop was enough cause for concern considering that most of our farmers practice mixed cropping.
Yes, the Department of Plant Protection and Research Institute reacted swiftly to contain the menace and even tested more chemicals that can be used against the pest on top of Cabaryl 85 Wettable Powder but that lull in attack must not be seen as an outright victory warranting people to relax or even go to sleep.
The pest can also re-surface in cotton, which normally remains in the fields even well after other crops have been harvested or in the irrigated crop, particularly the late planted or even that produced under dry land.
There is also the winter wheat crop to worry about, as there can easily be another outbreak if people drop their guard.
Also, there could still be huge outbreak of this fall armyworm next summer season, which makes it critical to educate and inform farmers accordingly on the habits of the pest and how it should be contained once it is spotted.
Farmers need to have adequate knowledge about the pest so that they can take adequate control measures.
They must also not experiment with chemicals because the pest may develop resistance. Once it becomes resistant, it means the traditional chemicals designed to control it will no longer work and crops may take a lot of battering while research on new lethal chemicals may be going on.
Chemicals that can be used for the effective control of the fall armyworm pest include Ampligo 150 ZC (Chlorantraniliprole), Coragen (Chlorantraniliprole), Super dash (Emamectin Benzoate) and Tide Plus 5WG (Emamectin Benzoate) and Superdash.
Standby spraying teams should always be on the ground and on the lookout for the pest instead of waiting to be called in when there is a problem.
It is not rocket science that the combination of spraying teams and equipped farmers will help curb the problem.
In a country with very high literacy levels like Zimbabwe, it is important to make sure extension workers and farmers are trained to scout and respond accordingly to the presence of the pest.
This time around the swift reaction may have been spurred by the fact that everybody was excited about the high prospects of a bumper harvest, thanks to Command Agriculture, but that cooperation and commitment should go beyond command crop programmes. The pest just does not respect any boundary.
Just as a precautionary measure, farmers should strive to have a knapsack sprayer so that it will be easy to contain pest outbreaks.
On the other hand, the Department of the Research and Specialist and Services should educate farmers on how best they can spray the pest.
Farmers sho0uld be educated on effective ways of applying the available chemicals. But scouting for the pest must also not stop once an outbreak appears to have been contained.
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