Teagasc is on the lookout for weeds and is encouraging farmers and agronomists to do the same.

Weed Watch is a new initiative designed to raise awareness about problem weeds and to encourage people to send suspect weed samples to be tested for herbicide resistance.

Watch out for some pictures of problem grass weeds from Teagasc and the Irish Farmers Journal in the coming weeks.

If you have grass weeds on your farm and want to share a picture to help other farmers identify those weeds, you can send those images to tillagenews@farmersjournal.ie.

We can keep submissions anonymous, but would like to share the county and the crop the weed is in. Make sure you pull or control the weeds after taking your picture.

Good control

Identifying grass and broadleaved weeds early on your farm is essential to get good control.

Many grass weeds and some broadleaved weeds are developing resistance to herbicides, meaning that the herbicides are no longer controlling the weeds.

June is a month when many grass weeds can be seen easily in crops. They grow over the crop and while it is often too late to control these weeds with herbicides at this time, they can be rogued or possibly spot-sprayed or cut before they go to seed.

In order to gather more data on weed resistance, Teagasc is trying to collect samples of these weeds.

So if you suspect herbicide resistance, follow the guidelines to secure viable seeds, which can be sent to Vijaya Bhaskar, weed researcher at Teagasc Oak Park.

For more information, phone 087-060 9409 or 059-917 0248 or email Vijaya.Bhaskar@teagasc.ie.

You can read about collecting and saving a sample for resistance testing by clicking this link.

Resistant weeds

Blackgrass and Italian ryegrass are the weeds most known for resistance in crops.

However, more resistance is emerging to common grass weeds, such as spring wild oats for example. Some meadow grass is showing signs of resistance to products such as Pacifica.

A sign of resistance build-up in a population is when a weed is controlled in one area and not in another area. So, you might have a green annual meadow grass plant beside a dead plant.

In broadleaved weeds, corn marigold, poppy, speedwell and chickweed are all showing signs of resistance to some chemistry.

When problem weeds are found, they can be very hard to control. They should be controlled by physical means if they cannot be controlled by using a herbicide.