Powerful, one-shot pest control in summer pulse and cotton crops

Ben Dawson, branch manager and agronomist at the B&W Rural stores at Narrabri and Collarenebri, says Skope insecticide on cotton crops helps limit applications against silverleaf whitefly, two-spotted mite and cotton aphid.

Controlling both sucking and chewing pests all in the one hit has been a positive move for northern croppers and the ability to do it in high value summer pulses as well as cotton has been a further bonus.

These crops are susceptible to a similar range of pests and growers often produce summer crops such as mung beans and cotton under irrigation during the same season.

Market development manager with ADAMA Jim O’Connor, says the introduction of Grindstone herbicide has allowed growers the flexibility to create their own post-emergent herbicide brews for controlling broadleaf weeds in cereals.

Skope insecticide, developed by ADAMA in Australia for local growers, offers one of the widest control spectrums in the industry and has become a powerful weapon against pests, as well as for helping busy applicators to avoid tank mixing hassles.

It contains 32.5g per litre of emamectin (Group 6) and 218g/L of acetamiprid, the first Group 4A active ingredient registered for sucking pests in summer pulses.

ADAMA Australia Queensland and NT territory market development manager Jim O’Connor says instead of tank mixing, it’s great to have a co-formulation of active ingredients to control a wide range of sucking and chewing pests in the one brew using a nice rate range.

“It’s the only product we are aware of which controls sucking and chewing pests in the one can,’’ Jim says.

“An application of Skope at 160mL/ha contains the equivalent emamectin as the maximum label rate of alternate insecticides,” he says.

“However it can be applied at up to 320mL/ha, so growers have the option to apply double the amount of emamectin on their crop with Skope if needed.

“It is a really robust rate range that is not available with any other product – you cannot get access to this rate range with another product.’’

As a result, the strong control provided by Skope can eliminate the need for later insecticide applications, also further improving its cost-effectiveness compared with alternate tank mixes that may be required.

Skope was originally registered for use in cotton, where it controls silverleaf whitefly, green mirid and green vegetable bug, as well as helicoverpa when required.

These latter three pests are also its target in mung beans, navy beans and soybean summer pulse crops through Queensland and northern NSW, while it adds bean pod borer and red banded shield bug in soybean as well.

Jim says the Groups 4A and 6 active ingredients in Skope also effectively provided an ideal rotation partner for insecticide programs, helping to relieve selective pressure for resistance particularly with Groups 28 and 22A insecticides.

“Certainly with helicoverpa, resistance is an issue we are aware of, with Groups 28 and 22A products developing some low levels of resistance in the field where they have been over-used,” he adds.

“However, there has been no recorded field resistance to emamectin in helicoverpa armigeria (cotton bollworm) populations in Australia.’

“So it’s a viable option to rotate Groups 28 and 22A insecticides with Skope and also get the benefit of sucking pest control from the co-formulation.’’

Nutrien Dalby agronomist Matt Skerman recalls previously recommending the use of Skope when threshold levels of helicoverpa, green mirid and green vegetable bug were identified in a crop of mungbeans.

The crop was at early flowering stage and Matt considered the two active ingredients in Skope would be “a good fit’’ to control all three species and allow opportunity to use alternate chemistry later in the crop cycle if required.

He says the insecticide worked well, resulting in a “clean check sheet’’ post-application, and, as the season continued, no further insect sprays were required.

It was a pleasing result at a competitive price compared with alternate mixes that would have been required to treat the same population.

Matt says another benefit is the opportunity to reduce selection pressure on the commonly used Group 28 chemistry.

He says the result was very encouraging for the future use of Skope in summer pulse crops.

In cotton, Ben Dawson, branch manager and agronomist at the B&W Rural stores at Narrabri and Collarenebri, says silverleaf whitefly, two-spotted mite and cotton aphid provided some of the biggest challenges for growers when present and Skope was helping to limit applications against the pests as a result of its wide control.

“There’s nothing out there that you can use to control insects like mirids, mites, aphids, whitefly nymph and potentially caterpillar. It has a wide range of uses over a wide timeline,” Ben says.

A short seven-day interval between application and picking cotton means Skope can be excellent for cleaning-up late season silverleaf whitefly populations prior to harvest, in turn reducing the risk of sticky cotton and quality downgrades.

When pest thresholds are reached, Skope should be applied with an adjuvant selected according to the primary pest targeted.

It offers translaminar activity, while limited systemic activity reinforces the need for thorough spray coverage.

Higher pest pressure situations can be targeted with higher rates for faster knockdown and longer residual control.

Ben says mid-season was a good application timing for Skope in cotton, just as whitefly numbers could typically build up.

“At this timing, it has also cleaned-up OP-resistant aphids and it has been very good on the mectin-susceptible two-spotted mite,” he explains.

“Aphid timings in crops can be random, but in the past these applications also worked out well against aphids,” he says.