New mango pest identified in Rio de Janeiro

The beetle Sternochetus mangiferae (mango borer or mango weevil) has already been identified in nine municipalities in Rio de Janeiro, all in the metropolitan region of the capital: Belford Roxo, Duque de Caxias, Magé, Mesquita, Nilópolis, Niterói, Paracambi, Rio de Janeiro and Seropédica . There are still no reports of the presence of the pest in other Brazilian states and the experts' concern is to prevent it from approaching commercial production regions for national consumption, such as São Paulo and Minas Gerais, and those that produce for export, such as Bahia and Pernambuco. .

The researcher at Embrapa Agrobiology (R.J.) Alessandra de Carvalho explains that mango is the fruit with the highest value in Brazilian exports, with the European Union as its largest customer, followed by the United States. The presence of the borer can put this sector at risk, as there are restrictions on the export of fruits and vegetables with the presence of quarantine pests, as is the case with Sternochetus. “Our trade balance could be affected if we lost these exports because of the pest”, emphasizes the scientist who advises: “If producers notice signs of the presence of the beetle, the ideal is to contact the state phytosanitary defense agencies or Embrapa, for through the Citizen Assistance Service (SAC). This is very important,” recommends the specialist when informing that Embrapa launched a explanatory publication for insect identification.

Currently, the municipalities where the pest was detected are considered a prohibited zone, with the movement of mangoes prohibited to areas free from the problem. Furthermore, the movement of fruits produced in Rio de Janeiro is subject to the presentation of a vegetable transit permit with Phytosanitary Certification of Origin (CFO), issued by the Plant Health Defense Coordination.

What is the mango borer Known as mango borer, mango seed weevil, mango weevil, stone beetle or mango beetle, the Sternochetus mangiferae is an exclusive pest of this fruit and its cycle of Life encompasses three stages: larva, pupa and adult. The young forms develop silently within the endocarp (pit), which makes their discovery very difficult.  Outside the fruit, the adult beetle usually carries out its main activities, such as locomotion, feeding and mating, at night, which also reduces the chances of being found by the farmer in the field. In its adult stage, it can measure up to 9,5 millimeters and is capable of flying over short distances, feeding exclusively on leaves, twigs and mango fruit when it is not at rest (diapause), without causing significant damage. During the day, it hides in mango tree trunks, in the canopy or under fallen leaves on the ground. During periods when the plant does not produce fruit, the insect enters diapause and during this period it does not move or feed.

What is the mango borer

Known as mango borer, mango seed weevil, mango weevil, stone beetle or mango beetle, the Sternochetus mangiferae is an exclusive pest of this fruit and its cycle of Life encompasses three stages: larva, pupa and adult. The young forms develop silently within the endocarp (pit), which makes their discovery very difficult. 

Outside the fruit, the adult beetle usually carries out its main activities, such as locomotion, feeding and mating, at night, which also reduces the chances of being found by the farmer in the field. In its adult stage, it can measure up to 9,5 millimeters and is capable of flying over short distances, feeding exclusively on leaves, twigs and mango fruit when it is not at rest (diapause), without causing significant damage. During the day, it hides in mango tree trunks, in the canopy or under fallen leaves on the ground. During periods when the plant does not produce fruit, the insect enters diapause and during this period it does not move or feed. 

Pest monitoring and control 

The researcher explains that knowing that the pest is restricted to the metropolitan region of Rio de Janeiro, it is necessary to know the level of infestation to adopt containment measures and prevent the spread of the pest to mango producing regions in Brazil. With this objective, the Ministry of Agriculture, Livestock and Supply (Map) signed a Decentralized Execution Term (TED) with the Embrapa Agrobiology (RJ) to carry out a detailed survey of the occurrence of the pest in the nine municipalities, train technicians from federal, state and municipal plant defense services to recognize the pest in the field, produce graphic material for phytosanitary education campaigns, evaluate forms of control, among other actions. This work is being coordinated by Alessandra Carvalho and seeks to understand the level of proliferation of the beetle, train technicians, expand knowledge about the presence of the pest in the national territory and support the Map with information to define the best way to contain or eradicate the pest. 

The scientist also leads an Embrapa project that aims to research aspects of the bioecology of this beetle, in addition to developing and evaluating sustainable monitoring and control tactics for the conditions under which the pest currently occurs in Brazil. Both TED and the project are formed by researchers and analysts from Embrapa Agrobiologia and Embrapa Genetic Resources and Biotechnology (DF).

According to the researcher, the two actions complement each other, since TED aims at emergency actions to support the Map, while the project seeks advances that can surpass existing knowledge, bring innovations and their applicability in Brazilian conditions “At this moment, all knowledge acquired in the project or in field actions has great validity, as nothing is known about this insect in Brazilian conditions and solutions proposed in other countries cannot always be used here or are really effective in containing the insect. S. mangiferae”, details Carvalho. According to her, there is a lack of information about controlling the pest worldwide, even though it has already been detected in many countries.

According to Antônio José de Araújo Moreira, from the Mapa Superintendence in Rio de Janeiro, all efforts to contain, control and eradicate the pest aim to prevent it from making mango production in the country unviable and damaging its internal and external trade. . “It is a fruit grown in almost all of Brazil. A business that generates more than US$200 million per year,” he highlights. He informs that as soon as the weevil was detected in Rio de Janeiro, the Ministry of Agriculture ordered an emergency phytosanitary survey to be carried out to find out the extent of the infested area.

According to the Embrapa researcher, preliminary results of the survey indicate that the level of infestation varies in the municipalities where the pest occurs. “After knowing more about the distribution of the pest in the region where it is currently restricted, it will be possible to determine the most appropriate action. If it is widely distributed, containment action is recommended; if it is restricted, we can think about eradication”, informs the researcher. 

Bury the lumps

There are still no records of chemical or biological products that combat the pest in Brazil, therefore, cultural control must be adopted. At this moment, the best way to contain the advance of Sternochetus is to collect fallen fruits or seeds from consumed fruits and bury them. 

This is a preventive measure that is already adopted in commercial fruit growing because of fruit flies, and should also be adopted in backyards, since the pest does not only occur in rural areas, but also in urban areas”, emphasizes the expert . Another warning made by the researcher concerns the transit of fruit: “Be very careful when taking mango fruit from the region where the pest occurs to other municipalities. There is a Normative Instruction (IN 34, of 05/09/2017) which declares the municipalities where the pest occurs as a prohibited zone and prohibits the movement of mangoes produced in them to free areas”. 

Help fight the plague Do not buy seedlings or seeds without certification. Never plant seeds whose origin is unknown. Do not take mango seeds or seedlings from one municipality to another within or outside the state of Rio de Janeiro. If you are traveling and buy mangoes at huts along the highway, or visit friends or relatives in the state of Rio de Janeiro and they offer you mangoes, consume them there. Do not transport fruits or seeds. Do not sell mango fruit that has the mango borer. If the mango fruits in your yard or farm have the mango borer, collect the fallen fruits and bury them. Also bury the seeds of the fruits consumed. If you want to sell mangoes from the state of Rio de Janeiro to other states, you must obtain the CFO (Phytosanitary Certificate of Origin) issued by a qualified technician, accredited by the Department of Agriculture. Contact the state's Plant Health Defense Coordination. If you notice any presence of the pest in any state, contact state or municipal phytosanitary defense agencies or Embrapa (Customer Service).

Help fight the plague

• Do not buy seedlings or seeds without certification. Never plant seeds whose origin is unknown.
• Do not take mango seeds or seedlings from one municipality to another within or outside the state of Rio de Janeiro.
• If you are traveling and buy mangoes at huts along the highway, or visit friends or relatives in the state of Rio de Janeiro and they offer you mangoes, consume them there. Do not transport fruits or seeds.
• Do not sell mango fruit that has the mango borer.
• If the mango fruits in your yard or farm have the mango borer, collect the fallen fruits and bury them. Also bury the seeds of the fruits consumed.
• If you want to sell mangoes from the state of Rio de Janeiro to other states, you must obtain the CFO (Phytosanitary Certificate of Origin) issued by a qualified technician, accredited by the Department of Agriculture. Contact the state's Plant Health Defense Coordination.
• If you notice any presence of the pest in any state, contact state or municipal phytosanitary defense agencies or Embrapa (Customer Service).

The size of the losses

The pest does not pose any risks to human health, but it causes damage to crops and threatens exports. Its presence reduces the germination capacity of seeds and also affects the development of the mango, reducing its length and circumference. The fruits tend to fall prematurely, which causes losses and damage to their structure.

Smaller fruits are not interesting for commercialization, but the losses go further. The sale of mangoes to the juice and pulp processing industry is also hampered, as the process can expose the pest. Furthermore, in late varieties, the hole caused in the fruit by the beetle's exit can facilitate the proliferation of fungi or other unwanted microorganisms, compromising the quality of the fruit. 

Awareness and commercialization

The beetle that causes the mango borer does not fly long distances, but occurs in both rural and urban areas, in large plantations or backyards. Therefore, public awareness is essential in the control process, since mangoes grown within the state of Rio de Janeiro cannot be transported, under the risk of the pest spreading to other regions. 

In theory, no hose is condemned for containing the pest, but fruits from trees that have borers should not be sold. “Containment measures must be taken based on the location of the property, as if it is in or close to production areas, greater care will certainly be taken”, explains Carvalho. Therefore, the work of the Technical Assistance and Rural Extension Company in Rio de Janeiro is important (Emater-Rio) with farmers and the work of technicians from the State Secretariat of Agriculture, Livestock, Fisheries and Supply of Rio de Janeiro (Seappa) in border inspection. 

More than 40 technicians from Emater-Rio and Seappa have already been trained to recognize the pest. A course for issuing a CFO was also held in Rio de Janeiro in 2019. In the state, these professionals are able to guide producers and traders about the problem, its risks and viable solutions for each case. “Everyone involved in the production, marketing and inspection network must pay attention, as only the combination of efforts and expertise can guarantee the expected positive results”, highlights the scientist.

Training in other states

At TED, training is planned for 2020 in Pernambuco, Bahia, São Paulo and Minas Gerais, along the lines of what was already carried out for Emater-Rio in 2019. “Training for issuing CFO is also necessary so that technicians can issue certificates for mango producing units, attesting to the absence of the pest and the possibility of selling the fruit and one of these was scheduled for March in Pernambuco, but was postponed due to traffic limitations imposed by the new coronavirus pandemic”, highlights the Embrapa researcher . 

The discovery of the plague in Brazil

O S.mangiferae It is present in several countries in Asia, Oceania and Africa and on some Caribbean islands. In Brazil, it was discovered in 2014, when a resident of the Campo Grande neighborhood, in Rio de Janeiro, contacted Embrapa's Citizen Assistance Service (SAC) requesting help regarding insects found inside a mango harvested in your backyard. After requesting photos and analyzing images of the fruit, researcher Alessandra de Carvalho recognized the possibility of it being a quarantine pest absent in Brazil. She went to the site to collect samples, verified the damage to the fruits, sent specimens of the insects collected to a taxonomist and, once the presence of the quarantine pest was confirmed, she followed the recommended procedures and officially reported the situation to the Ministry of Agriculture. 

From then on, with the help of Mapa, Seappa technicians underwent training at Embrapa Agrobiologia before carrying out an investigation into the possible presence of the pest in all municipalities in the state of Rio de Janeiro. Following these technical steps, the other states in the Southeast Region and all in the Northeast were trained and carried out a similar survey. “Initially, it was important to only verify the presence or absence of the pest to know where the Map’s actions should be concentrated”, explains the scientist. On September 5, 2017, Mapa released the Normative Instruction No. 34, which recognizes the occurrence of the pest in nine municipalities in Rio de Janeiro and prohibits the transit of fruits produced in them to free areas.