Intercropping saviour to maize production and food security

Fall armyworm has been one of the deadliest insect pests to be encountered on maize farms in Ghana and Africa, posing a threat to food security.

The insect since its identification in Africa during 2016 has spread to other countries, of which Ghana had its share – causing massive damage to crops in several West African countries.

The invasion necessitated a call to Ghana’s Parliament to declare an ‘agricultural state of emergency’. The invasion puts a GH¢560m agricultural project (Planting for Food and Jobs) at ‘serious’ risk.

To combat the infestation on maize fields, the Plant Protection and Regulation Service Directorate (PPRSD) of the Ministry of Food and Agriculture (MOFA) in Ghana, as a matter of urgency, released a list of recommended pesticides for Fall Armyworm control – but the worms still infest the farms.

According to experts, the fall armyworm creates small holes in the stems of maize plants and virtually destroys the entire crop.

The development of economically damaging insect populations depends on a number of factors: such as cropping practices, date of planting, insect migration patterns, parasites and predators, weather conditions – but the case of the fall armyworm is different.

Scouting for fall armyworm is necessary only in fields where larvae or their damage are noted, and measures are then put in place.

Maize has been one of the most widely-cultivated and consumed cereal crop in Ghana, and does not involve excess time to cultivate.

Over the past three years, however, sustainable cultivation of the crop has been threatened by the invasive insect pests called fall armyworm spodoptera frugiperda (J. E. Smith).

It has since become a great threat to Ghana’s food security as it is mostly devastating maize, the main staple crop

It is estimated that over 20,000 hectares of farmlands were destroyed by the pest as at April 2018, according to research scientist Dr. Mumuni Abdulai.

Yield-loss attributed to damage by the armyworm ranges between 26 and 40% in Ghana, of which national estimates of mean yield loss as at October 2018 was 470,200 tonnes – having a monetary value equivalent to US$177.3million.

Due to the efforts of government and donor agencies, a huge amount has been invested in the area to fight the insects – but all has proved futile, discouraging most youth from venturing into the sector to earn a living.

Every year, several crops are destroyed by theses deadliest insects resulting to post harvest loses in the country making efforts of farmers be in vain.

Toward sustainable management of fall armyworm damage to maize in the Northern sector of the country, entomologists and research scientists at the Savannah Agricultural Research Institute – led by Dr. Abdulai Mumuni and Dr. Jerry Nboyine of the Crop Protection Programme at SARI – have worked tirelessly on a number of strategies: such as assessing the efficacies of locally available plant extracts, government recommended insecticides, as well various intercropping systems for fall armyworm management.

Intercropping maize with a crop that is less preferred by the worms disrupts their movement, and thus limits damage to maize.

Also, some of the intercrop partners, such as Desmodium, have cues that repel pests.

The project, with funding from Alliance for a Green Revolution in Africa (AGRA), aimed at combatting worms affecting food security, unemployment and poverty in the country.

CSIR-SARI, under the project, also tested the insecticides that government through the Ministry of Food and Agriculture distributed to some farmers to fight the insects – which worked perfectly.

The insecticides tested included Eradicate, Emma Star, Bypel, Agoo and Adepa – all of which were effective at managing the pest; but their relative efficacies differed, with Bypel and Emma Star being most efficacious in the tests.

The institute also examined the various intercropping strategies for all armyworm management. Maize intercropped with sorghum, soybean, cow pea, groundnut and /or Desmodium were evaluated. The results showed that soybean or groundnut intercropped with maize were effective at reducing fall armyworm damage.

The new innovation makes the worms uncomfortable to stay on the crop for even a short period, according to the research scientists.

Furthermore, the farmers maximise returns from the use of their farmland in intercrops; while the legumes used to intercrop also have the added advantage of improving fertility for the farmer’s field.

Management of fall armyworm

The plant extracts tested were hyptis (hyptis suaveolens poit), Jatropha and neem in different concentrations. Overall, the extracts from these plants were effective at minimising fall armyworm damage and consequently increasing yields.

They were as effective as using synthetic insecticides in managing the worms.

“A major advantage of using plant extracts in fall armyworm management is that they are readily available in the environment, thus farmer can readily access them for use,” he said.

He said the new innovations were less harmful to the applicator and the environment compared to synthetic insecticides.

According to Dr. Abdulai, fall armyworm is a threat to food security and management practices such as the enumerated measures will contribute to significant reduction of the incidence and infestation levels of the pests and their damage for sustainable maize production.

Bi-rational pesticides such as the plants mentioned are encouraged for use in managing fall armyworms for sustainable maize cultivation in Ghana, he said.

Visits by some farmers to the trial field of SARI saw the maize crops planted in-between the vegetables yielding very well, while those planted solely were affected by the worms.

Some farmers within the Tolon district who had the opportunity to visit the field and saw the impact of the new measures to combat the worms expressed gratitude to the scientists for their tremendous efforts in helping fight the canker.

“It will go a long way to improve our crop yields and also encourage more youths to venture into the sector to grow maize,” they said.

“We will adapt to the new strategy to ensure our crops are not affected by the insects and boost our production.”

There is therefore need for massive campaigns to sensitise farmers on the new strategies to help fight the insects.