Chemical Pest Control archivos

Modes of action of systemic and contact agricultural insecticides

20 de May de 2022 No Comments

Classification of agricultural insecticides by mode of action Knowing how agricultural insecticides work allows us to make decisions about the type of insecticide we should apply to control the pests that attack our crops. Agricultural insecticides can be classified according to their mode of action, i.e. the way in which they eliminate pests. According to their mode of action, insecticides kill in two ways: systemic insecticides that act when ingested with the leaf; or contact insecticides that act when the pest is sprayed. A distinction is thus made between “contact” agricultural insecticides, which affect pest individuals when the insecticide comes into direct contact with the insects, and systemic agricultural insecticides, which are introduced into the plant, so that when the pest feeds on the plant, the systemic insecticide will start to work. Contact agricultural insecticides must necessarily come into contact with the pest, and therefore a higher coverage application of the insecticide will be necessary. On the contrary, systemic insecticides can be applied using a smaller number of drops, since what is needed is that they can reach the crop and not specifically the pest. In general, coverage of 50-70 drops/m2 is recommended in the case of contact insecticides versus 20-30 drops/m2 using systemic insecticides. As mentioned above, when systemic agricultural insecticides are applied to the plant, they penetrate its tissues even if they do not cover the entire surface of the plant. In some cases the products are applied to the soil and are absorbed by the roots, reaching all parts of the plant from there; in others, as occurs with foliar insecticides, they are applied to the leaves and, from there, they reach the rest of the plant. There are also insecticides that only penetrate the area of the plant on which they have been applied. Systematic insecticides do not penetrate the plant sap and, therefore, do not spread to other parts of the plant. Systemic agricultural insecticides Systemic insecticides remain on the plant for several days (sometimes even weeks) and act against a wide variety of pests. Preventive spraying should not be carried out too frequently, as pests can develop resistance to the insecticide. It is also important to know that the action time of systemic insecticides can be one week, so it is very convenient to take into account that the application date should be adjusted to the appearance of the pest, and to verify the effect on the pest one week after the treatment. A software like FuturCrop will allow us to know when the pest will appear again, and therefore we will be able to verify immediately the success of the treatment. Criteria for the choice of agricultural insecticides By mode of action Contact insecticides act on the target pest immediately after application and do not have a persistence of action over time. In general, contact insecticides cause the death of other insects, not only the pest that is attacking our crops. For example, we can combat a plague of aphids, and also kill their allies the ants, which provide them with food. However, we will also eliminate ladybugs, one of the most important natural predators of aphids and their larvae. In this sense, it is more advisable to use a systemic insecticide because it will eliminate the aphid infestation without harming other beneficial insects. Weather conditions Weather conditions also help determine which agricultural insecticide to use. Systemic and penetrating agricultural insecticides offer the advantage of being rainfast, so once the application has been made and 1 to 2 hours have passed, allowing the spray to dry, the product will not be washed off in the event of rainfall. On the other hand, agricultural insecticides with contact activity remain on the surface of the plant where they are applied. The products are susceptible to being washed away by rain and, therefore, the crop will not be protected, thus requiring repeat treatment. In general, they are able to exert a longer lasting control on the target pest for a longer period of time, which helps to avoid possible re-infestations. Más información Legislación internacional de Límites Máximos de Residuos de Plaguicidas (LMRs) en productos vegetales, Ministerio de Agricultura, Comercio y Turismo

Insect resistance to pesticides

22 de March de 2022 No Comments

The resistance of insects to plant protection products is caused by the excessive use of insecticides with the same active substances. The post explains how to prevent pest resistance to insecticides from developing

Insecticides for the control of fall armyworm

16 de December de 2021 No Comments

Fall armyworm, or Spodoptera frugiperda, is the larva of a nocturnal butterfly that mainly attacks maize, sorghum and rice, as well as some vegetable and cotton crops. Its larva causes great damage to crops. Its efficient control does not depend on insecticides for fall armyworm control. The two fundamental aspects of efficient pest control are monitoring and determining when the pest is most vulnerable to treatment. Fall armyworm monitoring Adult Monitoring Adults have a wingspan of 32–40 mm. In the adult male, the forewings are shaded in gray and brown, with triangular white spots at the tip and near the center of the wing. The front wings of females are less marked, ranging from a uniform grayish-brown to a fine mottling of gray and brown. The hindwings are iridescent silvery white with a narrow dark border in both sexes. Adults are nocturnal and are most active during warm, humid nights. Adults have a wingspan of 32–40 mm. In the adult male, the forewings are shaded in gray and brown, with triangular white spots at the tip and near the center of the wing. The front wings of females are less marked, ranging from a uniform grayish-brown to a fine mottling of gray and brown. The hindwing is iridescent silvery white with a narrow dark border in both sexes. Adults are nocturnal and are most active during warm, humid nights. Egg monitoring Females lay eggs on the underside of the leaves, in the middle part of the plant, in overlapping groups and layers between 100 to 300 at a time, covered by hairs from the abdomen. They are hemispherical of 0.5 mm in diameter, greenish freshly, then chestnut and with striations. When inspecting the crops, observing the underside of the leaves, it is possible to appreciate their contrast with the greenish color of the plant. Larval monitoring Damage to crops is carried out by insect larvae, which have up to 6 stages of biological development. When hatching eggs, the larvae have a light green color. They remain grouped in the lower part of the plants, sheltered between the leaves. They then feed on the chorion of the eggs, after which, if the host is not suitable, they migrate through a silk thread in search of food. They then act as cutters causing the loss of the small seedling by cutting the stem at ground level. In maize cultivation, the larva is introduced into the cob at the third stage. The larvae have a marked cannibalistic behavior, which is why a single larva is usually found inside the cobs, flowers or capsules. From the fourth instar they have darker tones and three dark yellowish and brown longitudinal lines. In the fifth stage the cephalic suture represents an inverted white “Y”, and they have a length of 35-40 mm. When disturbed, she drops by rolling up, resting her head on her body. In the later stages of development the larvae are most active at night. Monitoring of pupae To pupate, they bury themselves in the ground, 3-5 cm deep. Efficient control of fall armyworm Most treatment failures occur because they are performed late, when the larva is already inside the bud, cob, or capsule, from the third stage of larval development. Therefore, to perform efficient treatments, these must be performed in the first 2 larval stages. For this reason it is essential to be able to determine the moment in which the different phases of biological development of this pest occur. Currently there are tools that provide us with this information. Through FuturCrop, software that analyzes the weather conditions of your fields, you can receive in your email notices about the state of development of the pest and thus perform the treatments when they are more efficient. FuturCrop will also send you useful information for monitoring: the morphological characteristics of the pest, where to check its presence according to the different stages of its development, etc. In the application you can record from the smartphone the result of the sampling and the treatments carried out. More information Global action against fall armyworm, Food and Agriculture Organization of the United Nations (FAO)

Chemical control of the whitefly

3 de February de 2020 No Comments

By controlling the ambient temperature, we control the development of pests, specifically the whitefly, and we can determine the right time to treat.

TOXICITY OF PESTICIDES

12 de March de 2017 No Comments

The pesticide industry Global pesticide consumption was estimated at around $59 billion in 2016, 50% of which was in the developed countries of Europe and North America. This race towards the chemical protection of food began with what is the oldest organic pesticide, DDT (dichlorodiphenyltrichloroethane) which was synthesized by Müller in 1939, for which he received the Nobel Prize in 1948. Its use made it possible to combat major epidemics (typhus transmitted by lice and malaria transmitted by mosquitoes). However, its use is currently restricted in most countries because of its high toxicity and persistence, which causes serious ecological and human health damage. Characteristics of the agricultural pesticide industry Classification of pesticides Pesticides is an umbrella term for fungicides (to control fungi), herbicides (weeds), insecticides (insects), etc. There are also other classification criteria: by their mode of action, they are named according to the pests they control: fungicides control fungi, herbicides control weeds, insecticides control insects, etc. Pesticides can also be classified according to the following criteria: Toxic pesticides Short-term toxicity Toxicity a If we analyze pesticides for their toxicity, they are all toxic to humans and animals, but to varying degrees, depending on the dose and time of exposure. There are pesticides whose action affects not only pests, but also human biological processes. Such is the case of neurotoxic insecticides that act on nerve impulse transmission, common to insects and humans. This category includes organochlorine, organophosphate, carbamate, pyrethroid and nicotinoid insecticides. Endocrine disruptors are chemicals that alter the human and animal hormonal system. Studies on pesticide residues in food, based on data from the Spanish Agency for Consumer Affairs, Food Safety and Nutrition (AECOSAN), show that 28% of the foods analyzed contain pesticide residues (mostly within authorized limits). This percentage increases to 45% for fruits and vegetables. For example, 49 pesticide residues were found in pears, 16 of which were endocrine disruptors. Long-term toxicity In addition to short-term toxicity, there is another toxicity, the symptoms of which occur after exposure to small doses over a long period of time. But these damages are more difficult to assess and there are no conclusive studies. Environmental toxicity Pesticides also have an environmental effect. Most carbamates have low to moderate toxicity to mammals. However, bees are very sensitive to the presence of carbamates. But it is not only carbamates that influence bees. Two recent studies published in the journal Science show that the widespread use of neonicotinoid insecticides has negatively affected bee colonies. Bees are involved in seed and fruit production through pollination. Bees play a key role in biodiversity. But they also play an important role in food production. According to the Food and Agriculture Organization of the United Nations (FAO), one third of food depends on bees. Future of pesticides The European Commission presented in June 2022 a proposal to oblige a 50% reduction in the use of chemical pesticides in the European Union by 2030. Each Member State will propose different national targets, depending on the starting situation of each State. This proposal is part of the objective of creating a sustainable food system, according to the European Green Pact and the strategy “From Farm to Fork. Links De la From farm to fork. Strategy within the framework of the European Green Pact. European Green Deal Hazard classifications, FAO

Effects of Climate Change on pests

17 de December de 1019 No Comments

Effects of Climate Change on Pests The increase in temperatures due to Global Warming alters the biological cycle of pest development, extends the period of time during which they are present in crops, and expands the territories in which they are present. But these are not the only effects of climate change on pests. As the temperature rises, so does the metabolism of insects, increasing the number of generations per season, shorter reproductive cycles and, logically, increasing their population density. More reproductive cycles because pest metabolism is accelerated. Climate change not only means an increase in temperatures, but also in humidity and CO2. And these three increases largely determine the increased incidence of crop pests and diseases. Rising temperatures accelerate the metabolic rate of insects, and thus their reproductive rate. Some studies estimate that an increase of 2 degrees Celsius in the temperate zones of the planet could mean up to 5 additional biological cycles of certain pests. Insects belonging to the order Hemiptera and Thysanoptera (such as bugs and thrips), are the most benefited under these climatic conditions, since the increase in temperature favors their reproductive rate. In addition, the pests appear earlier in the crops (between 5 and 9 days for Carposina sasakii, Grapholita molesta and Phyllonorycter ringoniella in apple crops), and their presence in the crops lasts longer. Soil becomes more uniform in temperatures, therefore pests can live in other habitats. Climate change will increase the risk of pest spread in agricultural and forest ecosystems, especially in the colder Arctic, boreal, temperate and subtropical regions. The range of pests is expanding into new territories. New pests of tropical origin can survive in cold areas now considered temperate. A single unusually warm winter may be enough to favor the establishment of invasive pests in a geographical area. The tomato moth, Tuta absoluta, a tomato pest from South America, first appeared in Europe in 2006 and rapidly spread to almost all Mediterranean and Central European countries. It is a pest that rapidly accelerates its reproductive rate with increasing temperatures. Some pests, such as the budworm, which feeds on a large number of crops such as corn, sorghum and millet, and the Tephritid fruit fly, which damages other crops in addition to fruit, have already spread due to the warmer weather. The codling moth, Spodoptera frugiperda, has a life cycle that ranges from 35 to 61 days. Global warming of the planet causes this life cycle to shorten, increasing the number of generations and lengthening the period in which the pest can be active. New technologies for the new situation in the control of agricultural pests This requires that, in order to face these new challenges, the sector must adopt new ways of working that will allow it to foresee these changes and face integrated pest control and management with greater guarantees. Links Climate change fans spread of pests and threatens plants and crops, new FAO study Climate change impacts on twenty major crop pests in Central Asia, the Caucasus and Southeastern Europe, FAO

Category: Chemical Pest Control

Modes of action of systemic and contact agricultural insecticides

Insect resistance to pesticides

Insecticides for the control of fall armyworm

Chemical control of the whitefly

TOXICITY OF PESTICIDES

Effects of Climate Change on pests

Software de control de plagas

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Software de control de plagas

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