How does pesticide resistance occur

Upon exposure to insecticides, insects that do not carry the resistance genes die, thus allowing the individuals with the resistance genes to survive and reproduce, creating more resistant insects. With every generation the number of resistant insects increase.

Bt is a form of natural pesticide, as with any kind of pesticide the problem of resistance is almost unavoidable. Precaution must be taken and research must be done to understand and help prevent resistance with Bt. There are some steps Bt users apply to minimize resistance. Currently in the field, the diamondback moth is the only insect found to have developed resistance against Bt. Others are narrow, like some leaf spots and Fusarium wilt.

The spread of disease is largely passive for plant pathogens, unlike insects, which can move from site to site. Wind or fans , handling by workers and water are the most common way some plant pathogens get around our growing areas.

Examples of plant pathogens moved by water are Pythium and Phytopthora. Those easily moved by wind or fans are Botrytis, downy mildew, rust and powdery mildew. For plant pathogens the keys to resistance management involve a series of issues. First and foremost, the cause of symptoms must be determined. Using the wrong product for a disease results in no control, which can be confused with resistance. Use of the correct product at the correct rate and interval are the best ways to make sure you do not provide pressure on the fungus or bacterium, resulting in the development of resistance.

It is well-known that using lower than a lethal dose of a product targets the weakest or most sensitive individuals and builds the proportion of the population with a high level of resistance until it is the only thing present.

Application of a product too often in a program exposes the fungal or bacterial pathogen to a single mode of action, resulting in resistance development the same as insects and mites. This is especially true if you are using a narrow mode of action product, which does the same thing to plant pathogens as arthropod pests.

Tank-mixing or alternating products with the same mode of action does the same thing. It is always necessary to know the FRAC number to avoid this mistake by alternating numbers in successive applications. The next article in the series will address the history of pesticides in regard to the development of resistance to older and newer pesticides. His research and extension program involves plant protection in greenhouses, nurseries, landscapes, conservatories and vegetables and fruits.

Chase is president of Chase Agricultural Consulting. She has been retired from the University of Florida — Mid Florida Research and Education Center in Apopka since , but remains on staff as a professor emeritus. MasterTag understands that it is important to offer flexible options on custom-printed tags.

It enables growers to order custom tags in lower, more manageable volume requirements. Growers often need custom tags with unique or regional content as well as branding. But they also might need more variable data such as bar codes and pricing applied to their tags, says Gerry Giorgio, creative director at MasterTag.

That is where Group Run comes in. There are many advantages to this program. With Group Run, MasterTag assumes the responsibility to assemble an efficient print run across a group of growers. To prevent the pest from building-up resistance to the chemical, you should not use chemicals from the same resistance group over and over. Swap between chemicals from different resistance groups. A key element of effective resistance management is the use of alternations, rotations, or sequences of different insecticide mode of action classes.

Users should avoid selecting for resistance or cross-resistance by repeated use within the crop cycle, or year after year, of the same insecticide or related products in the same mode of action class. Integrating non-chemical approaches such as pheromone mating disruption and cultural controls can also help delay resistance. Consider crop residue options. Destroying crop residues can deprive insects of food and overwintering sites. This cultural practice will kill pesticide-resistant pests as well as susceptible ones and prevent them from producing resistant offspring for the next season.

However, farmers should review their soil conservation requirements before removing residues. Disclaimer: The information contained in this publication is based on knowledge and understanding at the time of writing. However, while all reasonable efforts have been made to ensure that this information is correct and current, the information covered is subject to change. Fruit Growers Victoria Limited does not assume responsibility and hereby disclaims any express or implied liability whatsoever to any party for any loss or damage caused by errors or omissions, whether these errors or omissions result from negligence, accident or any other cause.

P: 03 F: 03 E: info fgv. Become a member and take advantage of all that FGV has to offer. Download the Grower Membership package here. Home Services Latest updates Technical articles How do insects become resistant to pesticide? Once desirable traits are identified, these can be incorporated into new crop varieties through conventional breeding or genetic engineering. For example, apples have been bred to create a few varieties that are resistant to apple scab.

Even without specific breeding efforts, fruit crop varieties display a natural range of resistance to various pests and diseases. When monocultures of single varieties are planted, efficiency of production is traded for diversity of resistance to pests. Repeated use of the same class of pesticides to control a pest can cause undesirable changes in the gene pool of a pest leading to another form of artificial selection, pesticide resistance.

When a pesticide is first used, a small proportion of the pest population may survive exposure to the material due to their distinct genetic makeup. These individuals pass along the genes for resistance to the next generation. Subsequent uses of the pesticide increase the proportion of less-susceptible individuals in the population.

Through this process of selection, the population gradually develops resistance to the pesticide. Worldwide, more than species of insects, mites, and spiders have developed some level of pesticide resistance. The twospotted spider mite is a pest of most fruit crops and is notorious for rapidly developing resistance to miticides. Some plant pathogens have also become resistant to pesticides.