Pest advisories

Ragged holes and a wet sawdust looking mess in the funnel of young plants. It moves fast and it feeds at night, so the damage shows before the insect does.

Watch from

Two weeks after emergence, through the whorl stage

First sign

Small windowpane scrapes on young leaves, before the holes

Check

Walk the field and open the funnel on plants at 10 spots, not just at the edge

The damage is inside the boll, so a field can look healthy while it is being lost. Rosetted flowers and bolls that open badly are the signs above ground.

Watch from

Square formation onward, and hardest at boll development

First sign

Flowers that fail to open properly, described as rosetted

Check

Open green bolls at random and look inside. Nothing else finds it early

Patches of the crop dry off and collapse in a circle, which is called hopper burn. The insects sit at the base of the plant at water level, not on the leaves.

Watch from

Maximum tillering onward, worse in dense and heavily fertilised crops

First sign

Insects at the base when you part the plants, before any patch appears

Check

Part the hills and look at water level in several places across the field

A central shoot that pulls out easily and is dead while the rest of the plant is green. At the ear stage it shows as a whitehead, an empty panicle standing upright.

Watch from

Early tillering, and again at panicle initiation

First sign

Dead heart, a dried central shoot that lifts out with a light pull

Small orange to brown pustules in lines along the leaf that leave a powder on your hand. It spreads on wind and a warm humid spell after irrigation is what sets it off.

Watch from

Late tillering through grain filling

First sign

Powder on your palm after you rub a leaf

Report

Rust is watched nationally. Tell your agriculture officer if you find it

Shoots that wilt and droop from the tip early in the crop, then holes in the fruit later. The fruit looks fine from outside until it is cut.

Watch from

Vegetative stage, and through every picking

First sign

Drooping shoot tips with a small hole below the wilt

Do first

Cut and remove affected shoots and fruit at every picking. It matters more than anything sprayed

Clusters on the growing tip and on flower stalks, with a sticky film below them and ants working the plant. They multiply fastest in a cool dry spell.

Watch from

Flowering onward

First sign

Ants climbing the plants, often noticed before the aphids are

Worth knowing

Ladybirds arrive on their own and clear light infestations. Look for them before deciding