Resistance tests on grass-weeds, especially black-grass, can provide you with valuable information to help plan control strategies. Here are our four top reasons to get one done:
Testing black-grass seed for herbicide resistance will help you set out a long-term weed control strategy. Test results show the chemical groups or the individual products affected by resistance so you can plan your herbicide programme accordingly.
Resistance tests can determine which type of resistance has developed – enhanced metabolism resistance, target site resistance or both. In general, plants with metabolic resistance are still vulnerable to herbicides at early growth stages. Ben Giles outlines how to sample black-grass seed for resistance testing, read more about this here.
Without getting the results of a resistance test, it is possible to worsen problems unwittingly by using actives that weeds are resistant to, which is neither helpful for control or the bank balance.
Knowing which actives are under the most pressure can help in selecting crop protection products for the future. Once resistance is present it will not go away, but populations, and therefore yield loss, can be controlled through an integrated control programme.
Remember, resistance tests are only a snapshot into the level of the problem. Normally seed samples are taken from plants that have survived chemical control, so results will be biased towards the highest level of resistance. This highlights the need to know the proportion of the field population that the sampled black-grass plants represent in order to interpret to what extent resistance has taken hold.
If you have any questions, please contact your local CTM or Tweet @Bayer4CropsUK.
Our Ultimate Guide to Herbicide Resistance explains the science behind weed resistance, and how best to incorporate the information into your weed control management strategy.
