Pretty as a picture, gorse is a nightmare for landowners. Photo supplied.

Pasture pests are many and varied. There’s the likes of grass grub, black beetle, army worm, clover root weevil and porina larvae but, of course, weeds always pose one of the biggest problems.

Ragwort, gorse and thistle are examples of what farmers don’t want on their land with most aware that poisonous weeds will taint milk and affect production costs.

However, weed control is not always easy. Some sprays can damage clover so spot spraying should be considered and talk to the experts about biological controls for long term, low-cost treatment.

Council will also give advice on controlling pasture and environmental weeds.

Because weeds are spread as seeds via water, wind, birds, machinery, animals and hay, knowledge of how weeds spread can help determine an appropriate management plan.

Some basic means of controlling weeds include:

• Pasture management. To prevent weed intrusion, pastures should be regularly grazed. Avoid pugging, overgrazing or insect damage in order to maintain dense, thick grass which will also help keep weed seeds from germinating. Good drainage, the use of appropriate pasture cultivars, and optimum soil fertility will also help.

• Use of agrichemicals – primarily herbicide sprays which can be selective or non-selective. Some kill by contact, some kill by using the plant’s transportation system and others are synthetic hormones that distort and kill the plant. 

• Weed removal. Cutting, digging, ‘chipping’, pulling by hand, mowing, crushing and cultivation will help control weeds.

• Biological control. Useful when alternative control methods are not physically or economically possible. Biological control means using animals, insects or other organisms such as diseases to control weeds. The aim is to restore the natural balance between a weed and the environment by introducing an agent that attacks the weed in its native territory. The agent damages only the weed and while complete weed control is not possible with this method,

it will successfully reduce the number of weeds to an economic level. Although initially slow and expensive, once in place biological control programmes have low ongoing costs.

To prevent weeds from spreading remember to allow only clean machinery onto your property and be sure to use only seed that is certified as weed-free or certified low in weeds. Pest plants can be introduced into areas by using  uncertified seed.

Find out what is growing in your own garden. Farmhouse gardens may contain plants originally planted for their beauty but are now pest plants.  Ask advice from your council if need be.

And don’t forget those pests such as the grass grub. It is common in many pasture plants where the larvae attack the roots.

Susceptible pasture plants include clover and ryegrass. Lucerne and tall fescue are more resistant. Although grass grubs seldom cause severe economic damage, it is advisable to take control of this pest.

Insecticide sprays as well as cultivation in spring and mob stocking in late autumn-early winter will keep it at bay.

And remember some hard graft now will mean healthy pastures and consequently quality hay for next year.

A key technique for managing pastures, controlling access to pastures by livestock and lifting the overall productivity of pastoral farming is to employ closer subdivision, either with permanent or temporary fencing.