How to beat mealy bug

The bad news is there is a pest out there that may be damaging your pasture that you may not be aware of. The good news is that it has been out in the industry for a long time and there are some simple remedies for dealing with it.

Deane has been looking at some information by Chris Pennell of AgResearch.


Deane Carson, Southland Regional Manager


Adult mealy bugs are very small and pink, characterised by a white wax that they produce. They are easily confused with the Root Aphid which creates a similar yellow wax.

Mealy bug damage commonly occurs in January and is often associated with a dry spell. The most severe damage usually occurs in Autumn or early Winter and is particularly obvious when pastures are under stress. In this situation the damage can result in plant death.

They are tussock pests but can also target pastures when they are blown off the hill country and onto the plains. The Canterbury region is particularly effected by mealy bug because of the warm Norwest winds. In particular the Te Anau basin through to Mossburn is an area of risk due to the surrounding tussock country and dry summer conditions. Nelson, Marlborough, Manawatu and Alexandra are also problematic areas.

The good news is that Endophyte can protect ryegrass against attack. The recently released low toxicity AR1 Ryegrass has been shown to be as resistant to mealy bug attack as the wild type Endophyte. Wild type Endophyte has been proven to be toxic to animals causing ryegrass staggers in contrast to AR1 which has no toxic effects.

Grazing or irrigating when the pest is in the crawling stage may also reduce damage. The difficulty is identifying the crawling stage. Further research and field work is required in this area and there is also scope for work and development in the distribution of mealy bug in New Zealand because it is a newly recognised pest.