How to prevent establishment of Helicoverpa punctigera in Brazil

You've probably already heard of the fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae); small tomato borer, Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae); boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae); coffee borer, hypothenemus hampei (Coleoptera: Scolytidae); palm mite, Raoiella indicates Hirst (Prostigmata: Tenuipalpidae) and helicoverpa caterpillar Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). What do these insects have in common? They are all exotic pests that invaded and settled in Brazil, causing severe damage to national agriculture. The last pest on the list, H. Armigera, was discovered in mid-2013 and in the first year it caused losses of around 2 billion dollars (Czepak et al..

Well, on the world stage there are many other exotic pests with high potential for damage, as well as H. armigera. They are classified by Brazilian legislation as Absent Quarantine Pests (PQA). And by definition, an Absent Quarantine Plague (PQA) is understood to be one of potential economic importance for an area in danger, which is not present in the national territory (Brasil, 2016, p.7).

Some PQA have greater potential for harm when compared to others. A “cousin” close to the H. armigera, coming from the same center of origin (Australia), which haunts grain, cotton, vegetable and fruit producers around the world, and goes by the scientific name of Helicoverpa Punctigera (Wallengren) (Lepidoptera: Noctuidae). Because they are very similar, a lot of attention is needed in the correct identification of these species. Among the main morphological differentiations, it is possible to highlight that the larvae of H. Punctigera have black hair around the head and along the body, while H. armigera has light hair. In adult individuals of H. armigera it is possible to see two light spots on the lower wings, while in H. Punctigera There are no such spots (Figure 1) (Bellati et al..

Helicoverpa punctigera is an extremely polyphagous species that attacks approximately 130 species of plants (Zalucki et al. 1994; Cunningham et al. 2014) and nowadays it is restricted only to Australia (Figure 2) (Oertel et al., 1999).

There is great concern among phytosanitary regulatory bodies and producers around the world about the spread of H. Punctigera to other agricultural areas and this is due to a set of characteristics that allow it to survive and exploit different plants in different cropping systems. Its migration capacity stands out - around 2.000km (Rochester, 1999), its ability to remain in diapause ranging from 69-318 days (Zalucki et al., 1986) and high fecundity rate, since females have the potential to oviposit 1.500 to 1.800 eggs during a reproductive period of ten to 12 days (Zalucki et al., 1986; Furlong; Zalucki, 2017). However, in contrast to H. Armigera, has less ability to acquire resistance to insecticides.

Due to its potential for spread, several countries have made the entry of goods across borders more stringent. As a result of this effort, the United States Animal and Plant Health Inspection Service (USDA-Aphis) (USA), in 1999, managed to intercept two specimens of H. Punctigera (Kriticas et al. 2015). In Brazil, in 2015, there was suspicion of the presence of H. Punctigera, as an insect with similar characteristics was found in the Northwest region of the state of Ceará (Embrapa, 2015). The identification of this specimen showed that it was not H. Punctigera, but it can be said that a “warning light” was turned on for the possible arrival of this species, since H. armigera presents similar characteristics and is already present.

To prevent exotic pest species such as H. Punctigera, are introduced and disseminated in Brazil, investment in plant health is necessary, mainly in protectionist policies, using methods to prevent the introduction, establishment and dispersal of potential exotic pests (Maximino et al. 2004).

Given the importance of the dispersion of exotic pests in the world, introduction prediction techniques have become fundamental, as they are a lower-cost tool for controlling or eradicating the introduced pest, as the subsequent costs of a process of invasion are increasing and sometimes the problems generated are irreversible (Ziller et al., 2007). Border control, the establishment of quarantine systems to assess potential risks to biodiversity and the assessment of the invasive potential of species are some examples of tools used in these analyzes (Wittenberg et al., 2001; Worner; GEVREY, 2006).

To quantify this threat and develop an effective biosecurity policy, it is necessary to understand the potential sources of pests, the probability of arrival in the country and establishment in a given location, as well as estimating their possible impacts (Paini et al, 2011). In this way, the use of information about the biology and behavior of the species in places where it is invasive and the climatic data of these areas are very useful to complement the information regarding its natural habitat in modeling (Ziller et al., 2007; Paini et al., 2011).

Some countries in the world already use these risk analyzes of the introduction of exotic pests successfully, including Australia, the USA, South Korea and China (Zalucki; Furlong, 2005; Kriticos et al., 2015; GE et al., 2017; Byeon et al., 2018). In China, researchers used models to predict the introduction of Rhagoletis Pomonella (Walsh) (Diptera: Tephritidae) and Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) (Zheng et al, 2012). Kriticos et al. (2015) refined the Climex model, a software that uses climate and insect biology information and was used to alert American biosecurity managers to the potential for insect invasion. H. armigera in North America, identifying areas that are suitable for population establishment and growth during favorable seasons, whose crop production value in this environment is favorable to the introduction and establishment of H. armigera would represent 843 million dollars per year (Figure 3).

In addition to creating introduction models, it is possible to predict the temporal and spatial variation of endemic pests within the country. In 2005, Zalucki and Furlong conducted work using the Climex prediction model in which they defined the temporal variation in the abundance of H. armigera quality H. Punctigera at selected locations in inland Australia using historical meteorological data. In this way, it was possible to guide producers about the conditions and the most favorable period for the occurrence of pests.

Pest risk analyzes are powerful visual communication tools to describe where invasive alien species can arrive, establish themselves, spread or cause environmental, health and economic impacts, such as that caused by H. armigera in Brazil. These models aim to guide strategic decision-making and adopt the best tactics in pest management, such as possible import restrictions on goods from locations with potential pests or refining research design, developing more accurate models for interception of quarantine pests. , similar to that observed in Usda-Aphis (Vanette et al..

In Brazil, there are few studies using these modeling tools in phytosanitary protection, as it is a multidisciplinary science, that is, knowledge about mathematical modeling, biology and insect ecology is necessary. In 2014, through the São Paulo State Research Support Foundation (Fapesp), a pilot project was developed with mathematical models applied to insect control. However, given the importance of Brazil in the global agricultural scenario and the large volume of imported/exported goods, this is still little. It is necessary to engage phytosanitary regulatory bodies and researchers seeking greater international collaboration to build more robust models with the necessary scientific rigor so that this research can promote protectionist policies. 

Ruan Carlos de Mesquita Oliveira and Patrik Luiz Pastori, Federal University of Ceará