​Helicoverpa through Brazil: changing habits

Brazilian agriculture is, historically, one of the main foundations of country's economy, since the beginning of colonization until the 21st century, evolving from large monocultures to the diversification of production. Agricultural activity is part of the primary sector, where crops are grown and harvested for subsistence, export or trade.

According to agribusiness projections published by the Ministry of Agriculture, Livestock and Supply (Mapa) in June 2013, grain production estimates pointed to a harvest in 2013 of 184,2 million tons, in an area of ​​53 million hectares . These two variables are the highest ever achieved in Brazil over recent years.

For 2013/2014, expected production should be between 188 million and 204,6 million tons. This range of variation is a guarantee against the occurrence of changes over which there is no or little control, such as climate variations such as droughts and rains, or even the occurrence of pests that limit crops.

Part of the growth in the Gross Domestic Product (GDP) is being leveraged by soybean production, which rose in the 2012/2013 harvest, to 22,8% in the country and reached 81,5 million tons, as well as by the corn harvest, which increased 6,9%, a record 78 million tons, according to the National Supply Company (Conab). Nationally, the planted area increased by 10,7% and reached a record of 27,7 million hectares in the country, driven by rising prices in the international and domestic markets and early sales.

With each passing year, the demand for vegetables, vegetable or agricultural products, industrialized or in natura with the aim of meeting food, energy, clothing needs, among others. And this growing demand is a consequence of the population increase that the world is experiencing, in which, according to the UN agency for agriculture and food, the threshold of one billion undernourished people in the world has been exceeded, which means that one in every six people on planet Earth are affected by hunger. This historic high is the result of the impact of the financial and economic crisis that the world has been going through and the high prices of food products.

Every year, five million human beings are joining the army of the hungry in different parts of the world, making the reduction of hunger by 2015 more distant. To meet this population increase, government strategies aim to double the production of edible, fibrous and energy sources and therefore the processes adopted to achieve this scope are to improve the productivity rates of economic species and expand the cultivated areas through the opening of new agricultural frontiers or even encouraging the uninterrupted succession of crops. In either case, it tends to cause, directly and/or indirectly, the emergence of problems, highlighting the population increase of pests, native or exotic, understood here as all animal or plant species (insects, diseases, mites, weeds, etc.) that could cause losses or put agricultural production at risk.

Exactly in this context it is possible to understand the importance of the entry of an exotic pest into the country. These exotic species would be, by definition, primary, those whose introduction or dispersion threaten biological diversity, however, in current times, the real definition of exotic pests refers to organisms that, when introduced into new areas, cause economic and/or ecological impacts.

According to the Brazilian Society for Agricultural Defense, the issue of exotic pests is, indisputably, one of the most serious problems for the food, fiber and biofuel production chains, which can cause direct losses in the field and reduced access to markets, damaging competitiveness of the national economy. An example of this is the introduction, in the early 1990s, of the “B” biotype of Bemisia tabaci which quickly reached, despite all emergency programs and plans, the country's main agricultural frontiers. More than two decades have passed and the loss estimates are alarming, as it is estimated that the damage caused by this pest to Brazilian agriculture, added to the expenditure on chemical products, the only means, to date, used to control it, are already close to half a billion dollars, without taking into account the social impacts such as unemployment in the countryside and the consequent rural exodus that this pest causes in different regions of the country.

In addition to whitefly, it is also possible to mention Asian soybean rust, which was, after its discovery and dispersion in 2001, one of the diseases causing the greatest damage to Brazilian agriculture and continues to be a major obstacle to soybean production in the country. Other examples of pests introduced in recent years are the cotton boll weevil, the carmine cochineal, the star fruit fly, the citrus black fly, among others.

Phytosanitary threats, defined by the Ministry of Agriculture, Livestock and Supply (Mapa) as quarantine pests absent in Brazil and with potential for damage, can be known through a list published on the Ministry's website in which it is possible to find 21 species of mites , 63 species of coleoptera, 20 species of diptera, 21 species of hemiptera, seven species of hymenoptera, nine species of thysanoptera and 58 species of lepidoptera. Specifically, for this last group the list was recently rectified (IN nº 59, of 18/12/2013) with the exclusion of the quarantine pest H. armigera, as its presence in the country is confirmed and the Ministry of Agriculture declared, through recent ordinances, a state of phytosanitary emergency, due to the risk of an outbreak of the pest, for the states of Bahia, Mato Grosso, Piauí, Goiás, Minas Gerais and Mato Grosso do Sul.

Bioterrorism or delay in identification?

Following the official confirmation of the plague in Brazil, the possibility of being faced with a new type of terrorism was considered, one in which the aim is to destroy or make agricultural production in a certain location unviable, through the introduction of a certain pest. For the case of H. armigera, there can be many alternatives for introduction, such as, for example, imported product, natural dispersal, intentional introduction by an agro-terrorist action or involuntarily. However, this is not the concern that should be kept in mind, as the plague is currently a reality in several Brazilian states and even in neighboring countries, such as Argentina, Paraguay and possibly all of Latin America.

The factors that influence the stages of an exotic pest invasion process, as was the case with H. armigera in Brazil, can be explained according to researcher Denise Návia, from Embrapa Genetic Resources, based on the understanding of each of these stages, the first being defined as leading the exotic organism to new areas, as it has to survive the conditions of transport and be released into the new environment in good physiological conditions. The next stage is establishment, with reproduction and dispersal, starting to occupy larger areas. We then reach the final stage, when the ecological and economic impacts are perceived. From this perspective, it can be concluded that in the case of H. armigera It is likely that we are already in the last stage of the invasion process, as its identification was the result of the great economic impact it caused to a large part of the crops in the Brazilian Center-West, especially western Bahia.

In view of this, we cannot deny that this pest has possibly been present for longer than expected and that the famous "guesswork" at the time of its discovery and identification by "elimination of possibilities" prevailed for many years in the agricultural environment. Brazilian. This fact is proven in the countless reports from producers and researchers when they come across current and old photos of the pest, now officially called H. armigera and months ago confused in gender (Heliothis virescens) and species (Helicoverpa zea).

Furthermore, recent studies published by Csiro/Australia suggest that the plague may originate from different countries, including Pakistan, India, Australia or even China. Thus, possibly, it was not just with a single introduction that the H. armigera settled in Brazil. Perhaps there have been repeated introductions in a given area and in nearby locations, providing an increase in the chances of the pest's establishment, its hybridization and, as a consequence, the population explosion and geographic expansion, as was possible to verify in these last two agricultural years, mainly in the cultivation areas of the Brazilian Cerrados.

Therefore, it is a lesson for everyone involved in the Brazilian production chain the importance of correctly identifying the pests present in different cropping systems, as, by acting in this way, the chances of avoiding new invasions or even eradicating possible pests in Brazilian agriculture are large, even because the true phytosanitary defense is preventive.

Distribution, morphology and biology

Helicoverpa armigera is a Lepidoptera, from the Noctuidae family and Heliothinae subfamily, and its distribution currently reaches more than 90 countries in the world spread across Europe, Asia, Africa and Oceania. And now officially in Brazil, Argentina and Paraguay. As for the United States, numerous interceptions of the plague have been made in recent years, and the possibility that Central American countries become gateways to the aforementioned plague is a reality already considered by North American researchers.

Whether or not the plague has been officially confirmed extends across several Brazilian states, such as Bahia, Goiás, Mato Grosso do Sul, Mato Grosso, Rondônia, Roraima, Piauí, Maranhão, Tocantins, Ceará, Pernambuco, Sergipe, Minas Gerais, São Paulo, Paraná , Rio Grande do Sul and the Federal District.

Its identification is based, in principle, on the differences in the male's genitalia, which makes it even more difficult for technicians and producers to recognize and confirm the presence of this pest in the field. Therefore, when in doubt, it is best to look for trained personnel for correct identification, even because the possibility of being faced with hybrid individuals is a reality, given that populations of H. armigera e H. zea they are being found frequently, occupying the same space in corn crops and mating between the two species has already been reported in foreign literature.

The evolutionary cycle from egg to adult H. armigera can vary from 40 days to 45 days, depending on weather conditions. The adults of this pest are nocturnal, preferably flying at twilight, as observed in the field, but they can also fly in the middle of the night and, less frequently, some stragglers are found during the day.

Whether or not adults remain in the area can be determined by finding floral nectaries and using them for food. Thus, female pests emerge from galleries in the soil two to four days before males, which is a convenient biological strategy to protect offspring from unsuitable conditions for their development, such as, for example, the absence of hosts. The inhospitable environments will likely force females to move to other regions, leaving behind pheromone trails so that males can reach them.

Therefore, females are attracted to crops mainly due to the inflorescences and their nectar, which are crucial for them to be able to carry out their oviposition, with each female being able to oviposit, on average, from a thousand to 1.500 eggs during her entire cycle. of life, and it is important to highlight that a female is capable of laying around 400 eggs in a single night.

These eggs can be laid individually or in small groups in the same location, always in the highest, most tender and hairy parts of the plant and, preferably, in the inflorescences or in the forming fruits. However, this is not a rule, as eggs are also found on leaves, shoots and stems. Finally, it is important to highlight that these eggs are always very visible to the eyes of a good observer.

The eggs are rounded, whitish in color, about 0,5mm in diameter and have southern striations that go from one pole to the other. 12 hours after oviposition, they are straw-yellow in color and close to hatching they form a dark area at the apex, giving a grayish appearance to the egg, corresponding to the caterpillar's head capsule. Hatching can occur in two to three days in the hottest periods of the year and in four to 12 days in the coldest periods.

In the first instars, the caterpillar H. armigera It has a body with abundant dark bristles and shiny bases, demonstrating a certain similarity to caterpillars of other species of the Heliothinae subfamily. The dark hairs are observed until the third larval instar, as from the fourth stage onwards, the caterpillar begins to display characteristics that are easy to observe, such as numerous whitish hairs, including on the head capsule, a protrusion on the fourth abdominal segment in the shape of a “ saddle", commonly dark in color, but always shiny, the last abdominal segment presenting an inclined plane, the integument having a slightly leathery appearance and, finally, it has the habit of curving the cephalic capsule towards the first pair of false legs, giving it a peculiar appearance that differentiates it from caterpillars of other species usually found in culture.

The larval stage is completed in six instars and lasts 13 to 22 days, depending on climatic conditions. The caterpillar can reach up to 4cm in length in its last instar and, at the end of the cycle, it seeks the soil to pupate, building a chamber where it can remain for ten to 15 days until the adult emerges. If climatic conditions are not favorable, this phase can continue for at least 140 days or until soil humidity and temperature are suitable for the beginning of a new pest cycle, thus presenting a facultative pupal diapause.

The adult of H. armigera It can easily disperse across crops and remain in this environment for many generations, as long as there is food, or even migrate great distances, traveling at up to 30 km/h and reaching 1.000 km in two to three days, this being a natural habit of the pest in its adult stage, regardless of climatic conditions and the presence or absence of hosts in the area.

Host crops and damage

A H. armigera is known, mainly, for its ability to locate and use a wide range of hosts and this is one of the factors that contribute to the “pest status” that this moth has on several continents around the world. More than 180 plant species are listed cultivated and wild as hosts of the pest, among them it is possible to mention corn, wheat, sorghum, grasses, barley, sesame, tomato, tobacco, potatoes, flowers and ornamental plants, such as petunias, gladioli, snapdragon, hibiscus, tail cattail, carnations, lupins and dahlias, sunflower, alfalfa, rapeseed, mustard, broccoli, cabbage, canola, beetroot, ginger, peanuts, castor beans, chickpeas, string beans, soybeans, peas, oregano, okra, cotton and fruit trees such as orange, lemon, strawberry, passion fruit, papaya, banana and grapes, as well as weeds such as milkweed, pigweed, horseweed, borage, bredo, white mallow, among others.

In Brazil, reports of the presence of the pest in cultivated and spontaneous plants increase every day. At the moment, H. armigera has already been found in soybeans, corn, millet, sorghum, wheat, cotton, tomatoes, peppers, peppers, lettuce, watermelon, coffee, citrus, sunflower, tobacco and weeds such as horseweed, horseweed, Santa Maria grass, pigweed and guanxuma, proving its great ability to adapt to different crops. It is also noticed that both the caterpillar and the adult are extremely associated with the reproductive parts of the host plants. Furthermore, adult forms can recognize the hosts through which they developed in the larval stages. Information like this is extremely important information for monitoring and controlling alternatives for different agricultural or wild landscapes in the country.

However, it is worth highlighting that the mere presence of immature stages of the pest in cultivated or wild plants does not necessarily imply that it is a host. For this to occur, the insect must complete its cycle in the crop and the adults obtained must be fertile and, until this happens, it can only be considered that the plant is a potential host for the pest.

A H. armigera It is capable of attacking all stages of a crop's development, feeding on leaves, stems, stems, flowers, pollen and fruits. In the first instar, the caterpillar, after breaking out and feeding on the chorion (eggshell), remains nearby for up to two hours, when it then begins the process of scraping the leaf parenchyma, and then moves to the vegetative or reproductive parts. of the plant, piercing, leaves, branches, stems, flower buds, flowers and fruits.

In crops such as soybeans, if the infestation occurs in the vegetative phase, the caterpillar normally remains protected in the trefoils that are still forming, building small shelters with a fine web, which in a few days dismantle due to the opening of these trefoils, and can then be easily found on the upper surface of leaves even in the hottest hours of the day. However, greater caterpillar activity is observed at cooler times, especially at dusk.

The biggest impact on soybean production occurs when the plant reaches its reproductive phase, as in this case the caterpillar moves to the center of the plant in search of flowers, pollen and pods, and in the latter it can consume it entirely or make holes in it. circular, opening galleries in order to consume the grains in formation or already formed, causing irreversible damage to the crop. The voracity of the caterpillar increases as it passes through its stages, and it is important to highlight that 80% of the material consumed by a caterpillar H. armigera occurs in the last three larval instars.

It can also cause significant damage to the inflorescences and growing points of soybean crops, as it indiscriminately pierces everything it encounters. And, despite having a certain preference for the upper parts of the plant, this pest can move from the top to the base, piercing and destroying stems, petioles, pods and flowers of the same plant, however, with a notable preference for grains, from which it can obtain the proteins and carbohydrates it needs for its development. This voracious behavior and the habit of attacking the pods without consuming them entirely can result in extensive damage even when the number of large caterpillars is relatively low and therefore leads to the conclusion that many caterpillars are not needed. H. armigera to cause damage to soybean crops, as well as any crop in which the pest is established.

Monitoring suggestions

For H. armigera, it is necessary to understand that monitoring is essential for decision-making in relation to control tactics and this mainly means a change in habits, as without the use of this technique it will be difficult for the producer to stop the increase in the pest in the crop. . Therefore, the recommendations are based, in principle, on frequent monitoring, in the vegetative phase once a week and in the reproductive phase, intensifying inspections at least twice a week, observing not only the target crop, but also all other plants around and around the area, as the pest is polyphagous and, normally, producers maintain more than one crop on their properties.

Maintaining trained and committed field monitors is essential for the success of any monitoring program, especially when dealing with a pest with a high destructive capacity, such as H. armigera, as it will be based on the sampling results that a decision will be made regarding the best time for application and the tactic to be used. It is up to the producer to constantly offer courses and training for these monitors who are key players in monitoring the areas. Furthermore, this commitment must also come from agronomic assistance, so that producers have technical support in decision-making throughout the crop development process.

While studies on H. armigera are not explored in depth in Brazil, it is worth maintaining the monitoring already recommended for pests that exhibit the same behavior and/or are from the same subfamily, as is the case of Heliothis virescens in cotton.

In the case of soybean crops, the recommendation would be to divide the areas into plots and, when monitoring, always take into account the vegetative and reproductive phases of the crop (see monitoring action sheet). It is also important to monitor with pheromone-baited traps that are used to capture adults when they intend to reproduce. In this way, countless males are attracted and, when they enter the traps, they end up stuck to a base with glue. These traps must be spread around the areas, as indicated by the manufacturers, and monitored daily to check adult population peaks.

Control decision-making must take into account all phases of the pest and in the specific case for soybean crops, the following parameters can be adopted for now: newly emerged crops: 10% of plants with eggs or small larvae; crops in the vegetative stage: a maximum of three (eggs or small caterpillars)/m, and in case of long summers, do not exceed the number of one egg or one small caterpillar/m; crops in reproductive phase: maximum 0,5 small caterpillar/m.

If the number of adults and light eggs found in the samples is greater than the number of dark eggs and small caterpillars, it is recommended to wait for a few days or until the number of adults in the traps decreases before deciding to spray agrochemicals, thus avoiding sequential applications that can make soybean crops economically unviable.

It should be noted that first and second instar caterpillars are easier to control, however, only monitoring can ensure the detection of the pest in its initial stages. Therefore, the failure to control the H. armigera in the 2012 harvest, in several areas of cultivation, resulted in great losses for many, and could be repeated significantly this year, as there is still a general lack of knowledge about the importance of the caterpillar in the country's various agricultural crops and, therefore, consequence, which insecticides and which doses should be applied. The producer is, on his own, doubling doses of products, producing homemade insecticides, making mixtures, combining up to three insecticides, normally recommended for the crop, however, not yet officially studied for the control of H. armigera. Therefore, the effects of these products on the pest, its natural enemies and the environment are unknown.

Therefore, it is worth remembering that the pest must be controlled not at its first signs, but rather in its early stages. By acting in this way, producers, in addition to reducing their production costs, can avoid the indiscriminate use of agrochemicals that increase the risk of environmental contamination and can help preserve natural enemies present in crops.

Proposals for control tactics for H. armigera

Integrated pest management, through the use of appropriate control tactics for each type of crop, is essential for maintaining the H. armigera under acceptable conditions without causing harm to agricultural production.

Thus, the use of biological products, selective insecticides and the adoption of chemical control based on the different mechanisms of action of each product are essential for the success of integrated management, as well as resistance management. It should also be noted that applications for controlling H. armigera, regardless of the type of product used, should preferably be done at night, and can be started in the evening.

Furthermore, a practice widely used by producers, which is the widespread scheduling of insecticide applications, must be abolished from Brazilian production systems, as, in most cases, it is unnecessary, indiscriminate and causes irreversible biological imbalances in the country's agricultural areas. Another issue to be reviewed concerns the use of tank mixes, as it is always good to remember that the antagonistic or synergistic effects of this practice, which is so common among producers, are unknown by research, in addition to not being regulated by the competent bodies.

For chemical and biological control of H. armigera (see attached table) most products have emergency registration and to obtain definitive registration in the country, several studies will still be necessary, from verifying effective doses to the impact of these products on the environment and human health.

It is also recommended to use ancient agricultural practices that provide adequate conditions for the good development of crops and, at the same time, interrupt or alter the life cycle of pests, promoting adverse situations for their development or even preventing the perpetuation of these pests in areas with agricultural crops. Such as, for example, the immediate destruction of ratoons and crop residues, as well as the elimination of spontaneous plants or tigueras. And although there are laws that oblige producers to adopt these practices mentioned above, many still insist on keeping crops taken over by tigueras or ratoon plants and only realize the error when they realize the damage.

Another viable option would be the use of trap crops or bait planting. The idea is simple, as it consists of planting strips of attractive crops around crops, preferably ones that flower quickly and are sown in advance of the final planting of the area, with the aim of attracting migrating adults to kill, through applications of insecticides or attractive mixtures based on insecticides. Furthermore, the trap culture must be maintained with sequential applications of insecticides to contain young forms resulting from possible escapes and, whenever possible, give preference to selective insecticides, thus preserving any natural enemies that may be present. Not forgetting that this practice will only be effective if there is strict control of pests and diseases in the trap crop, as without this this crop would merely multiply the pest.

The use of light traps or traps baited with pheromones to detect the entry and population peaks of the pest must be adopted continuously and by all producers. It should be noted that in the case of using light traps, females of different species of insects instinctively oviposit before being captured, resulting in a greater concentration of eggs in plants that are close to the traps, a fact that must be observed in the case of H. armigera. Therefore, if the producer has to choose between the two methods, it is considered that the use of traps baited with pheromones is more practical, mainly for the identification and counting of the adults collected, as, normally, what is obtained in light traps is a cluster of insects of different species, most of them so damaged that their identification is impaired. Furthermore, this volume of insects can lead the farmer to mistakenly conclude that there is effective control.

Among the biological control options for H. armigera through natural enemies, egg parasitoids, belonging to the genus Trichogramma, represent a globally recognized group, in addition to those already created and sold on a large scale by Brazilian biofactories, being, therefore, a very viable alternative for both small and large producers, given that the attitudes of H. armigera In crops in general, they are found, most of the time, in the upper third of the plants, favoring parasitism. However, the adoption of this tactic makes it mandatory to monitor adults and eggs of the pest in question so that the releases are effective in controlling them, as the parasitoids have little dispersion capacity and need to quickly find the pest eggs. H. armigera for an effective reduction of the pest in the area. Another important point is in relation to the adoption of selective products, as if this care is not taken, the possibility of survival of the parasitoids will be compromised.

Regarding the natural biological control of H. armigera It can be said that its establishment will depend on the preservation of natural enemies present in the area and for this to occur it is important to avoid the use of extremely toxic or low selectivity insecticides. The efficiency of natural enemies, classified as predators, parasitoids and entomopathogens, will also depend on their specificity, reproductive potential, search capacity and dispersal in the area. The main species of natural enemies observed in agricultural crops controlling the different phases of H. armigera are predators of eggs and/or caterpillars of the genera orius, Nabis, geocoris, Podisus, Zellus, as well as the litterbug, ladybugs, carabids, earwigs, wasps and spiders. Parasitoids of the genus can also be included in this list. Campoletis, flies from the Tachinidae family and finally the white disease called Nomuraea rileyi.

Turning the soil can also be a way to eliminate possible pupae remaining from previous crops, taking into account the susceptibility of the pupal stage and the shallow depth, up to 10cm at most, in which the pest is lodged. Furthermore, this mechanism helps to make the adult emergence process unfeasible, as it destroys the insect's exit tunnels. However, this practice is only recommended after the fact that pupae are found in the soil and if neighbors around the property also opt for this measure.

Finally, the production systems currently used by producers can contribute incisively to the process of establishing H. armigera in Brazil and, therefore, it is up to everyone involved to change habits, with thoughts focused on the common good, so that Brazilian agriculture becomes increasingly sustainable, competitive, with lower risks of human poisoning and environmental contamination, preserving flora and fauna from different regions of the country and with lower risks of resistance to insecticides.

Spreadsheet of actions per 100ha plot for use in monitoring and management programs in soybean crops* – Model prepared for Goiás by the School of Agronomy of the Federal University of Goiás. 2013

Culture phase	Assessment type	Number of points	Number of samples/point	Exclusive
Vegetative	Visual inspection of the upper third of the plant using a 30 magnification pocket lens	5	2	Mark one meter of soybean row and inspect the first open and semi-open trefoils of each plant for the presence of eggs (light and dark) and caterpillars (L1/L2; L3/L4; L5/L6), quantifying them and recording them in a specific monitoring sheet for the pest.
	Cloth method²	5	2	The cloth is adjusted only on one side of the crop line and beats vigorously to extract all insects, which are identified, quantified and recorded on monitoring sheets.
Reproductive	Visual inspection of the upper third of the plant using a 30 magnification pocket lens	5	2	Mark one meter of soybean row and in the upper third of each plant, inspect trefoils, flowers and pods looking for the presence of eggs (light and dark) and caterpillars (L1/L2; L3/L4; L5/L6) quantifying them and noting them on a specific monitoring sheet for the pest.
	Cloth method²	5	2	The cloth is adjusted to one side of the crop line and beaten vigorously to extract all insects, which are identified, quantified and recorded on monitoring sheets.
	Pod inspection	5	10	The number of pods attacked or not by the pest is quantified on the plant.

Culture phase

Assessment type

Number of points

Number of samples/point

Exclusive

Vegetative

Visual inspection of the upper third of the plant using a 30 magnification pocket lens

5

2

Mark one meter of soybean row and inspect the first open and semi-open trefoils of each plant for the presence of eggs (light and dark) and caterpillars (L1/L2; L3/L4; L5/L6), quantifying them and recording them in a specific monitoring sheet for the pest.

Cloth method²

5

2

The cloth is adjusted only on one side of the crop line and beats vigorously to extract all insects, which are identified, quantified and recorded on monitoring sheets.

Reproductive

Visual inspection of the upper third of the plant using a 30 magnification pocket lens

5

2

Mark one meter of soybean row and in the upper third of each plant, inspect trefoils, flowers and pods looking for the presence of eggs (light and dark) and caterpillars (L1/L2; L3/L4; L5/L6) quantifying them and noting them on a specific monitoring sheet for the pest.

Cloth method²

5

2

The cloth is adjusted to one side of the crop line and beaten vigorously to extract all insects, which are identified, quantified and recorded on monitoring sheets.

Pod inspection

5

10

The number of pods attacked or not by the pest is quantified on the plant.

¹The monitor also makes management decisions based on samples of adults obtained through pheromone-baited traps installed in the same field. ²Recommended method for when the plants are larger and there is no danger of damaging them.

Click here to read the article in Revista Cultivar Grandes Culturas, issue 177.