Red palm weevil

The youngest, central fronds — the 'spear' standing at the very top — start to wilt, yellow and droop while the older outer fronds still look green. On the trunk and leaf-bases you'll find holes oozing a rusty-brown, sticky fluid, wads of chewed, wet fibre (this is called frass) that looks like brown sawdust, and often a sour, fermenting smell. Put your ear against the trunk on a quiet day and you may even hear the grubs chewing inside.

a big rusty-red to reddish-brown beetle about as long as your thumb (3–4 cm), with a long, curved snout and usually a few dark spots on the shield behind its head. You will rarely see the adults — they hide, and fly mostly at dusk. The real damage is done by its grubs: fat, legless, creamy-white maggots with a hard brown head, each about as fat as your thumb, buried deep in the soft heart of the palm where you cannot see them.

— a shiny black beetle with a horn that bores in from the top and leaves neat V-shaped cuts in the newly opening fronds; its damage is clean and dry, not oozing and smelly. And plain yellowing of the lower, older fronds with no holes, no frass and no smell is usually drought or hunger (a nutrient shortage), not the weevil. Red palm weevil always attacks the central crown and leaves those oozing, fibre-packed holes.

keep watch all through the palm's life — from young, developing palms right up to old, fruiting ones — and step up your checks in warm weather (around 20–35 °C) and in the weeks after any pruning, storm damage or transplanting, because fresh wounds are exactly what draw the weevils in.

don't only check the palms next to the path. Walk a large 'W' across the whole grove so you pass every corner and the middle, and stop at every single palm — a grove is small enough to check tree by tree, and missing one hidden infestation is how you lose the lot.

the central spear and crown for wilting or a leaning, lop-sided top; the trunk and leaf-bases for oozing holes, wet brown frass and that fermenting smell; and the ground around the base for empty, fibre-covered cocoons — a sign that weevils have already bred there and flown off.

There is no safe level with this pest. A single weevil caught in a pheromone trap — a baited bucket that uses the weevils' own gathering-scent, plus a lump of palm, to lure and drown the adults so you can count them — anywhere in your area, or the very first palm showing crown wilt or an oozing hole, means act immediately. Waiting for a second sign usually means waiting until a palm is already dying.

Weevils are drawn to fresh cuts and their smell, so avoid wounding the trunk and crown, prune as little as you can, and when you must cut, seal the wound (with tar, mud or a wound paint) and do it in the cool, dry season when weevils are least active. Never leave cut palm trunks, stumps or heaps of old fronds lying around — they are perfect breeding sites, so clear and burn them.

Hang pheromone traps (the baited buckets that lure and drown adult weevils) through the grove — and, best of all, do it together with your neighbours. The weevils fly in from next door, so mass-trapping works far better when the whole area does it at once. Empty and re-bait the traps regularly, and treat every catch as an early warning to go and inspect the palms nearby.

The moment a palm shows its first oozing hole or wilting spear, treat it with entomopathogenic nematodes — microscopic worms that hunt down and kill the grubs inside the palm, and are harmless to you, to the palm and to animals. Flush the nematode mix into the crown and straight into the oozing holes so it reaches the grubs, and keep it moist and out of the hot sun so the tiny worms stay alive.

Because the grubs are hidden deep in the stem, an outside spray is useless: you need a systemic insecticide — one that travels in the palm's own sap to reach the grubs inside, unlike a contact spray that only kills what it directly touches — injected or drenched into the crown of an infested palm, following your local plant-health or quarantine rules. Cover your skin, eyes, nose and mouth, work in the cool of the day with the wind at your back, and keep it away from children, animals, water, bees and the nuts or fruit. Respect the pre-harvest interval (the set number of days you must wait after treating before the harvest is safe to eat), wash yourself well afterwards, and rotate to a different chemical group each time so the weevils don't build up resistance.

A hollowed palm with a collapsing crown cannot be saved and has become a weevil factory — cut it down and burn or bury the whole trunk and crown at once to kill the grubs still inside, and never move the infested wood to another area (that is exactly how the weevil travels to new groves). Because it spreads across a whole district, report it to your local agricultural or plant-health officer — this is a quarantine pest, and beating it takes the whole area acting together, not one farm alone.