Rice bugs

At the top of the plant the panicle (the head that carries the flowers and grains) fills with empty or half-empty grains that stand upright instead of bowing over with weight. The grains that do fill carry brown or black spots and stained, shrivelled kernels — farmers call this 'pecky' rice. A sharp, foul smell hanging over the crop is often the very first clue, before you even spot a bug.

a slender green or straw-brown insect about 1.5 cm long — a little longer than a grain of paddy — with very long, thin legs and antennae, so it looks like a tiny walking blade of grass or a thin twig. The young ones (nymphs — the wingless early stage) are bright green and look like smaller, thinner adults. They cling to the grain heads, most active in the early morning and late afternoon, and drop or fly off the moment you disturb them, giving off that foul stink. Look too for the eggs: tiny dark reddish-brown discs laid in a neat row along the top of a leaf blade.

with the broad, flat, shield-shaped stink bugs — rice bugs are slim and stick-like, not wide and flat — or with grasshoppers, which chew ragged holes in the leaves and give off no smell. The slender shape, the long legs, the stink, and the fact that it feeds on the grain, not the leaves, are what mark out the rice bug.

Rice bugs only matter once grain is forming, so scout from heading (when the grain heads push out of the stem) through flowering and the milk stage (when a squeezed grain oozes white liquid) until the grain firms up. This is your crop's most vulnerable window — miss it and the damage is already done.

The bugs sit openly on the heads then and move slowly; by the midday heat they drop down low and hide, and you will undercount them. Walk a big 'W' shape across the field so you cover the four corners and the middle, not just the strip beside the path — and check the edges next to grassy weeds first, because that is where the bugs invade from.

At each stop, either look closely at the grain heads on 10 hills (a 'hill' is one clump of rice plants that grew from a single planting point) for bugs and fresh spotting, or take a sweep net — a cloth bag on a hoop of wire — and swing it 10 times through the tops of the plants, then count what you caught. Use your nose too: a strong stink over the crop means they are already there in numbers.

Count the bugs on your 10 hills — about 10 bugs in total, one per clump, means spray now. With a sweep net, 5 bugs in 10 sweeps is the same warning level. Below that, keep watching every few days: in warm, humid weather (around 24–32 °C at flowering and grain fill) their numbers can climb fast.

Agree with your neighbours to plant the same variety at the same time, so every field flowers and fills grain together. Staggered or late planting gives the bugs a long, moving buffet and lets their numbers explode; synchronised planting keeps the vulnerable window short and shared across the whole area, so no single field is left standing as the last green target.

Keep the bunds (the raised earth walls and paths between the paddies) and field margins cut and free of grassy weeds — those weeds are where rice bugs shelter and breed before they move onto your rice. Harvest promptly and don't leave late, half-filled patches standing, which become a bug nursery for every field around you.

Tiny parasitoid wasps (harmless wasps that lay their own eggs inside the rice bug's eggs, killing them before they hatch), together with spiders and predatory bugs, quietly destroy eggs and young nymphs for free. Don't spray broad poisons that wipe these helpers out too — that only makes the next outbreak worse.

In the cool of early morning, while the bugs are still sluggish, sweep them off the heads with a net or a leafy branch and destroy what you catch. A traditional trick is to hang something foul-smelling — rotting snails, crab or fish — on sticks at the field edge; it lures the bugs away from the grain to where you can gather and kill them.

If you reach 1 bug per hill (or 5 in 10 sweeps) during heading to milk stage, spray a registered pyrethroid (a common group of contact insecticides — they kill only the bugs they land on or that walk over the treated heads, so cover the panicles well). Spray in the cool of early morning or late afternoon, with the wind at your back; cover your skin, eyes, nose and mouth; keep it well away from food, drinking water, children and bees; and wash yourself and your clothes afterwards. Because you are spraying so close to harvest, respect the pre-harvest interval (PHI — the least number of days the label says you must wait between your last spray and cutting the crop) so no unsafe residue reaches the grain. To stop the bugs becoming resistant (surviving a chemical used so often that it no longer kills them), rotate to a different chemical group each time instead of spraying the same one over and over.

you cannot win field-by-field when bugs keep flying in from staggered neighbouring fields, so take it to the whole community to plant and harvest together next season and to clear the shared weedy margins. When it is too late → cut your losses: once the grain has firmed past the soft-dough stage the bugs can no longer feed on it, so stop spraying (you would only add cost and residue) and harvest as soon as it is ready. Cut and thresh badly pecked patches separately so the stained grain does not drag down the price of your clean harvest.