The main aim of the project is to improve the control of Redlegged earth mite (RLEM) and Lucerne flea in pasture, without the use of insecticides. Both of these species are resident pests, meaning the population is established within a paddock and carries over from year to year.

Conventional control of these pests frequently relies on spraying insecticides or using insecticide seed dressings when sowing pastures. Although these control measures help reduce damage at establishment, they are undesirable for other reasons. Insecticide sprays are toxic to many beneficial species, and seed treatments rely on products that are likely to be withdrawn from market at some stage. In both cases as stand-alone control measures, they do not manage the population of pests within a paddock.

Populations of resident invertebrate pests can be manipulated by changing the habitat in which they live. We have designed a new sequence for sowing (renovating) existing pastures which incorporates a multi-species crop, but instead of sowing the multi-species seed at the same time, a delayed sequence approach will be used. The main concept is to plant cereals first and clover last (several months later). Effectively this should starve out resident pests such as Lucerne flea as they do not have preferred pasture to feed on, then sow the susceptible pasture species after the pests have been reduced due to lack of suitable feeding sources and habitat. The species planting sequencing looks something like this and will be sown with 2-4 passes over at least 6 months. This sequencing of planting pastures will help to reduce the number of pests such as Lucerne flea whilst allowing beneficial insects such as snout mite to build in numbers.

With a more balanced pest:beneficial population, the natural biological control should be able to maintain pests at a level that won’t limit pasture growth or require the use of chemical options to manage pest populations.

Trials need further testing and monitoring.