IMIDACLOPRID, THE INSECTICIDAL ACTIVE INGREDIENT IN HOMBRE? AND ZORRO? IS MORE THAN JUST AN INSECTICIDE.

Abstract

Establishing cereals can be challenging due to problems associated with insects, diseases and other stresses on plants associated with the soil and environment. International experience has shown that the use of a seed treatment product like Gaucho can provide growers with a tool to improve plant establishment, and manage some of the insects that negatively impact on plant growth. Bayer CropScience has undertaken extensive research in Australia that demonstrates how the seed treatment insecticide imidacloprid, available as Hombre (tebuconazole + imidacloprid) and Zorro (triadimenol + imidacloprid) can be used to improve the yield of wheat, barley and oats.

Introduction

Imidacloprid is active on a wide range of sucking and biting pests and is registered for the control of aphid feeding damage and management of barley yellow dwarf virus in cereals. It is also an ideal component of any integrated pest management strategy in cereals. Imidacloprid, the active ingredient is absorbed and translocated throughout the seedling. This allows beneficial species to attack pests with little or no effect from the seed treatment insecticide. Current foliar insecticide options impact negatively both on the beneficial species present while controlling the pest populations being targeted.

The insecticidal active ingredient, imidacloprid, in Hombre and Zorro, in environmental stress situations, can be more than an insecticide. As an additional benefit, Hombre and Zorro may offer Stress Shield™ effects, assisting plants to overcome environmental stress during establishment. Global research has found that some members of the chloronicotinyl chemistry group can produce positive growth responses in the absence of obvious pest pressure. The responses that can be seen include an increase in the growth rate or an increase in the green colour of the plants compared to the untreated plants. Research found that imidacloprid (e.g. Gaucho, Hombre and Zorro) is the only member of the chloronicotinyl chemical group to positively influence abiotic plant stresses such as stress from extended dry periods (Thielert, 2006). Further research found that imidacloprid resulted in the greater production of 6-CNA within the plant’s mitochondrion during times of extended environmental stress. 6-CNA is a key component required by the plant during the respiration process.

Methods

Since 2003, in excess of 42 research and demonstration trials have been carried out across Australia to qualify and quantify the benefits that Hombre and Zorro can offer in the production of cereals. Hombre and Zorro treated seed was compared to the standard treatment options (i.e. Hombre verses Raxil® and Zorro verses Baytan®), with the same seed source being used in each trial to maintain genetic equivalence. Plant establishment (counts) and yield were assessed.

Results and discussion

In 75% of trial observations a profitable yield advantage was gained with the use of Hombre or Zorro.

Across 42 trials, an average yield improvement of 350 kg/ha was achieved as a direct result of the imidacloprid component in the seed treatments, Hombre and Zorro.

Hombre and Zorro treated plants showed improved foliar and root system growth rates.

The yield improvements were found not to be specific to a climatic region. Generally the larger return on investments resulted from regions with yield potentials less than 5 t/ha. .


<3.0 t/ha 3.0 - 5.0 t/ha >5.0 t/ha Average
Number of observations 8 25 9 42
Average yield: t/ha 2.1 4.04 6.03 4.1
Income: $/ha ($200/t) $420 $808 $1,206 $820
Additional Yield: t/ha 0.38 0.4 0.19 0.35
Additional Yield: $/ha ($200/t) $76 $80 $38 $70

The Australian results in wheat, barley and oats support global research findings with barley that show that imidacloprid can be more than just an insecticide. Trial results in the absence of any obvious pests showed that imidacloprid, the insecticidal component of Hombre and Zorro can assist in maximising the grain yield potential of cereals.

References

Thielert, W 2006, ‘A unique product: The story of the imidacloprid stress shield’, ed. Dr M Esters, Pflanzenschutz-Nachrichten Bayer 59:73-86, Bayer AG, Agriculture Centre, Monheim Germany, ISSN 0340-1723

Contact details

Ken Blowers
Bayer CropScience
391 Tooronga Road
Hawthorn. Vic. 3123
Ph: 02 6027 0904
Fx: 02 6027 1107

Hombre®, Zorro®, Gaucho®, Raxil® and Baytan® are Registered Trademarks of Bayer
Stress ShieldTM is a Trademark of Bayer