3 July 1998

Liquid insecticide method is precise, safe & easy to use

Moving towards pesticide-

free storage is a desirable

goal. But on many farms it

is not yet practical.

Here Charles Abel

examines the way one

Northants farm is making

careful use of insecticide to

keep grain free of pests

A NEW grain drier installation prompted Northants farmer Richard Tarry to revise his approach to routine insecticide applications to keep the farms grain pest free throughout long-term on-floor storage.

Until recently wheat and oilseed rape grown on the 990ha (2450-acre) farmed by Pytchley Farms near Kettering was stored after on-floor batch drying.

One unit eight miles from Pytchley Grange housed grain dressing, insecticide dust applicator equipment and drying floors for 1500t. Meanwhile, Pytchley Grange relied on three 250t floors supplied by ambient air fans.

But with the main 3000t on-floor store being in a converted stock building at Pytchley Grange grain needed moving about a lot to get dried, dressed and treated, recalls Mr Tarry.

"The 3000t store was never designed with the headroom for fitting a grain floor, so we have to ensure that when the grain goes in it will store safely," explains Mr Tarry.

"We seldom sell any grain until after Christmas. With large volume storage you cant afford to take risks. If mite or other grain pests get a hold we might have to move, treat and dress nearly 3000t of grain. The small cost of an insurance treatment, at about 40p/t, is well worth it."

To improve drying and focus most of the farms storage around the main on-floor store at Pytchley Grange a new continuous flow 35tph Law Dennis drier was recently installed.

But adding an insecticide dust applicator was out of the question. "The grain is pretty dusty as it comes out of the drier, so applying a dust would just be too dangerous. Using a liquid applicator actually helps damp the dust down. It is also more accurate and easier to handle," says Mr Tarry.

"Moisture and temperature are the main concerns. 10C and 14% moisture are our aims, but in practice, with high ambient air temperatures or grain straight from the drier, it is difficult to get the temperature down immediately."

After an attack of rust red grain beetle some years ago the farm took the decision to treat all grain into store with approved insecticide.

"We are using liquid preparations for pre-harvest hygiene applied by sprayer and hand lance to the walls and the floor of the store. And we use smoke bombs to fumigate the roof space. The new Allman applicator we purchased last autumn allows us to treat grain as it comes into the building."

Actellic D (pirimiphos-methyl) is applied to grain at a rate of 16ml of product in 0.75 litres of water a tonne. An integral flow meter on the applicator shows the actual application rate during use. That gives a clear picture of progress, particularly if a blocked nozzle or other restriction occurs.

Recording grain throughput and actual flow rate at intervals during treatment helps provide evidence of accurate treatment for assurance schemes, claims manufacturer Allman.

The self-contained, electrically powered pump regulator and flow meter sits in the corner of the store, with a delivery hose feeding a single flat fan nozzle spraying a fine mist on to the grain as it leaves the delivery chute from the drier.

"We have used Actellic dust for many years, but feel that liquid is more likely to maintain accuracy. Airborne insecticide dust is inevitable and we feel more comfortable applying the liquid OP preparation. It will also allow us to use other liquid insecticides as they become available, concludes Mr Tarry.

Speedy checks

Rapid detection of grain contaminants, such as ergot, rodent droppings, or insects, will be possible using a new computer system developed with HGCA funds. It compares visual images with recorded data to assess 3kg samples in as little as three minutes. Commercial partners are being sought to develop the laboratory invention for trade use.

Store limitations mean Northants farmer Richard Tarry is unable to rely on cooling and drying to avoid grain pest problems. A new liquid insecticide applicator (above) ensures greater precision, safety and easier operation, protecting over 3000t of on-floor storage in a former livestock building (below).