Rural: Munch bunch use pasture for free lunch

Robin Casey says now is the time to hit grass grubs and porina using insecticide. It's possible to do so even in wet weather. PHOTO/FILE

Independent Wanganui fertiliser broker Robin Casey is again warning that the district is infested with grass grub and porina and now is the time to act.

For successive seasons in recent times Mr Casey has discovered infestations of almost epidemic proportions on several properties he monitors throughout the wider region.

While he has long advocated soil and herbage analysis to reveal on-farm problems, in this case he has gone back to basics, employing the simple spade test to uncover the grass grub and porina infestation.

"How often do you take a spade to your paddocks?" he asked.

"It's a prudent thing to do at times, but not as a replacement to soil and herbage analysis. What I've discovered is that both grass grubs and porina are around in large numbers and that causes problems. If you find more than one porina and or more than four grass grubs in a spadeful of dirt, you have a problem.

"Numerous properties I monitor are infested and that suggests a wider problem of almost epidemic proportions. Now is the time to treat pastures with insecticide and that can even be done in the rain, unlike most other applications," he said.

Grass grubs eat away at pasture root systems, while porina graze the grass on the surface, destroying paddocks and reducing feed stocks.

It has also been revealed both bugs reduce the plant's ability to extract trace elements and nutrients from the soil. That, he said could be confirmed through soil and herbage tests and rectified simply by acting on the laboratory results.

A recent visit to his GP unearthed another potential snag for farmers.

"I went to my doctor and, long story short, discovered my blood pressure was way too high. I then went to another person I knew with a blood-pressure machine and my reading was quite a bit lower. I then went to a mate's home, where he had a portable pressure machine, and the reading was well within the safe range - obviously someone's equipment was faulty."

That got him thinking about soil and herbage testing regimes.

"Different companies test in different ways; all are within the framework of New Zealand regulations, but it comes down to who is reading the results and how they interpret them. When dealing with lab results, please ensure the technician or consultant you are working with can read the results correctly," Mr Casey said.