Latest grain research report clears Tanzanian maize shipments saying they are free from viral infections

The Tanzania Plant Health and Pesticide Authority have released an updated report on the occurrence of Maize Lethal Necrosis Disease and its associated viruses.

The Director General of TPHPA Prof. Joseph Canisius Ndunguru stated here that the authority has undertaken an extensive research in the field and in the maize grain seeds throughout the mainland Tanzania.

The latest findings, whose March 2024 report was made available in Arusha, suggest that maize grain seeds from Tanzania do not pose a risk of transmitting viruses causing MLND in the region.

“We decided to conduct thorough studies to satisfy ourselves that the country grain consignments are safe,” explained Prof Ndunguru.

“Maize is an important food and income earner for rural and urban dwellers in Tanzania. Productivity of maize in Africa can be affected by diseases like Maize Lethal Necrosis Disease (MLND),” added the expert.

Following the first report of the occurrence of MLND in Tanzania, the Ministry of Agriculture through its Tanzania Plant Health and Pesticides Authority (TPHPA) conducted monitoring surveys to establish the areas affected by the disease and identify the viruses causing the disease in the maize fields and grain shipments.

Undertaken in pursuant to Plant Health Act No.4 o 2020; the comprehensive survey of MLND was conducted in the Lake Zone (Mwanza, Kagera, Shinyanga, Mara), Northern Zone (Kilimanjaro, Manyara, Arusha) Southern Highlands Zone (Ruvuma, Njombe, Iringa, Rukwa and Katavi), Central zone (Dodoma and Singida), Western Zone (Tabora) and the Eastern Zone (Tanga and Morogoro).

According to the TPHPA, Maize lethal necrosis disease (MLND) of maize (Zea mays L.) is caused by a combination of Maize chlorotic mottle virus (MCMV) and any of the cereal viruses in the Potyviridae group including Sugarcane mosaic virus (SCMV), Maize dwarf mosaic virus (MDMV), Maize mosaic virus (MMV) and Wheat streak mosaic virus (WSMV).

Reverse transcription polymerase chain reaction (RT- PCR) method was used for detection of these viruses in the field-collected samples and from maize grain seed samples collected from the Malawi-Tanzania border at Kasumulo,  in December 2023.

Laboratory analysis of the samples did not detect any of the viruses from the maize grains as well as the field samples from the major maize producing regions in Tanzania.