In the recent years there is increasing ability in pests to survive the exposure to chemicals due to;
- Transportation of insects and mites all over the world.
- Fewer pesticides with different mode of action being available in the market for pest control.
- Also the need to reduce environmental impact and harm to human health.
Resistance to pesticides is the result of spontaneous genetic mutation and selection of pests. Some will survive exposure to pesticides and their offspring will carry the genetic make-up of their parents and will become a greater proportion of the population with each succeeding generation.
The determining factors in development of resistance include;
- How frequent are the genetic mutations
- The reproduction speed resulting to high population development
- Mode of dispersal of pest either by walking or flying
- Frequency of the pesticide applications
Reasons for resistance to pesticides include:
- Accelerated secretion as the chemical doesn’t get sufficient time inside the pest insect’s body to be able to cause serious damage.
- Accelerated degradation due to breakdown of the chemical inside the pest insect’s body.
- Pests avoiding contact with the chemical.
Repeated applications of the same pesticide may induce cross resistance
to other pesticides that have a similar mode of action leading to high pest infestations. It is very important to use chemicals in different groups with different mode of actions in order to reduce pest resistance.
Recommendations :
- Complementary use of bio-agents like;
- Magneto 10EC (azadirachtin 6g/l + matrine 4g/l) 0.5ml/l
- Baciguard 16 WDG ( bacillus thuringiensis var, aizawai 16000) 0.5g/l
Magneto® 10 EC is Broad spectrum, systemic with contact and stomach action insecticide for control of Aphids, thrips, white ies, bollworms and mites on Roses, and Aphids, White ies, Thrips, Caterpillars, Leaf miners on snow peas.
2) Input of natural enemies/ predators to control pests
3) Use chemicals correctly after understanding the ecological behavior of the target pest and its different life cycles and select the right spraying technique for better distribution, coverage and intrusion.
NB; It is important to observe the number of recommended applications & interval between applications. Also for each spray tank mix with integra at a rate of 2ml/L for better coverage.
