Biological Control Agents Introduced To Counter New Mango Mealy Bug Pest In Uganda

The Ministry of Agriculture, Animal Industry and Fisheries (MAAIF), in collaboration with the Food and Agriculture Organization of the United Nations (FAO), the National Agricultural Research Organization (NARO) and the International Institute of Tropical Agriculture (IITA), working with the District Local Government, today released biological control agents (BCA), as a pest management strategy to control the Mango mealybug (MMB) in Ntungamo District. Presence of the Mango mealybug (Rastrococcus invadens Williams), locally known as Kanyananga- Oruhumbo, was reported in November 2021 in Ntungamo District, Sofia cell, Kafunjo parish, Mirama Hill- the immediate border between Uganda and Rwanda. Since then, efforts have been geared towards the pest’s management.

In response, the Government of Uganda, through MAAIF, supported by FAO and IITA, released the biological control agents (BCA) specifically two parasitoid wasps- Gyranusoidea tebygi and Anagyrus mangicola to control the MMB in Ntungamo. FAO and the Government of Uganda have reviewed all the scientific data to ensure the introduction of these insects is safe and effective. The BCA methodology for pest management is the best approach to manage the mango mealybug because chemical pesticides have not been effective in controlling the pest. MAAIF, FAO and partners believe that the BCA will relieve the stress of farmers, who, fearing food insecurity and income loss, hired fumigators to spray their mangoes around July/August 2022. Much as the fumigants are highly toxic to the environment, MMBs are still present.

Speaking at the event to release the biological control agents, Hon. Fred Bwino Kyakulaga- Minister of State for Agriculture noted that despite Government efforts to transform the 38 percent of the population still stuck in the subsistence economy to the money economy; while increasing production, productivity, value addition and agro industrialization, the agriculture sector is faced with many challenges including diseases and crop pests such as Mango mealybug.

“This pest can cause up to 100 percent yield loss if not handled timely. This pest has a waxy covering substance which protects the pest against any pesticide spray making it extremely difficult to control”, he said. “It is therefore crucial that farmers report any new pest in to any agricultural staff in their communities and that all the officers, leaders and farmers play their roles to support the biological control of these pests. This will help us to manage the pest before it spreads deeper inland into other areas”, he added.

Protecting mangoes from mango mealybug damage can serve to protect the fruits that are important in the diets of the people in the community and also income that can be obtained from selling mango fruits. Processing of mango into juice is growing but pests can hamper the growth in the processing industry for Uganda.

According to Antonio Querido- FAO Representative in Uganda, millions of dollars are spent to combat pests, money and investment that could have gone into other targeted agricultural investments, resulting in significant agricultural transformation and positive outcomes for farmers, agripreneurs, and actors along different agriculture value chains- Leaving No One Behind.

“FAO has, for instance in response to mango mealybug of concern here in Ntungamo and the country at large, spent about 200 000 US dollars (about UGX 760million) in capacity development, mobilization and raising of insects that can control mango mealy bug in Uganda. In 2017 and 2018, FAO contributed 500 000 dollars (UGX 1.9billion) to Government efforts in building capacity for management of Fall armyworm in Uganda. In 2020 and 2021, about 11 million dollars (about UGX 41billion) was mobilized for responding to desert locusts including the procurement of vehicles, equipment, pesticides, awareness, and training and on other innovations”, he said.

“Plant pests have always been a challenge for agriculture production. We have had to play catch up to develop the technologies to gain the upper hand to reduce their impact. In a globalized world, we have seen that pests move further and faster more than ever! Climate change is facilitating this”, he added.

However, Ntungamo District Local Government is optimistic that the introduction of the biological control agent will restore farmer’s hope and mango farming in the area.

“We thank the Ministry and FAO for the swift response to managing the mango mealy bug, which destroys leaves and fruits. This will ensure that the pest is contained and does not spread to other areas”, said Sam Mucunguzi, the District Chairperson of Ntungamo District. “Although farmers have registered losses this season, we believe that since a solution has been introduced, the next season will be better”, he added.

Mango mealy bug in East Africa

First reported in the East African Region, in Rwanda in 2019 and Burundi in 2020, the Mango mealybug (MMB) attacks over 100 plant hosts and mangoes are most preferred. The MMB has other alternative hosts including citrus, guava, bananas and pawpaws. The pest can cause 89-100 percent yield loss in severely affected mango orchards and is very hard to control by pesticide spray since it has a waxy covering substance which hinders the pesticide to penetrate and kill the pest.

Fungicides will not work because this is an insect pest and not a disease. Since they multiply in numbers rapidly, MMB is also known to develop resistance to many pesticides and some of these pesticides are restricted by international trade partners including the European Union. It is thus recommended that the safest and most effective control of the MMB is by biological control using parasitoid wasps. The wasps have been successfully utilized in MMB control in West Africa.

According to the Centre for Agriculture and Bioscience International (CABI), the mealybug feeds on the tree and produces droppings which make the leaves black and sticky. This lowers the strength of the tree, and its production of mangoes. During a heavy attack, a whole part of the tree looks blackish in colour. This insect pest lowers the yield and quality of the mango and can be passed from one tree to another, by wind, water, contaminated farm equipment and people. MMB colonies appear as white masses under the leaves of the mango and can be mistaken for a fungus. The white mass is just thousands of mealybugs feeding on the leaves, sucking its juices.

Uganda has witnessed crop devastation and loss of income of its people, owing to migratory and occasional pests affecting various crops. For instance, Fall Armyworm was first experienced in Uganda in 2016 and is now spread over the country affecting maize and sorghum production. The recent desert locust invasion in 2020, in some countries in Africa (including parts of Uganda) – the worst in decades, greatly affected crops and food production