Passion fruit brown spot

small brown spots that start pinhead-size and grow into round-to-irregular brown patches, often with a paler tan centre and faint rings inside, like a target or an archery board. Each spot is usually ringed by a yellow halo where the green fades. As spots join up the leaf yellows and falls, and a badly hit vine loses much of its leaf.

long, dark brown, sunken streaks, most often right at a node or where a leaf or tendril joins the stem. A streak that runs right round the stem rings it (girdles it) and kills everything beyond — the shoot and its flowers or fruit wilt and die back. This stem attack is what makes brown spot so costly.

round, sunken brown spots that start small and slightly greasy, then spread, with the centre going wrinkled and leathery. The fruit shrivels, rots and drops early, and even lightly spotted fruit is scarred and cannot be sold fresh.

Woodiness virus gives a patchy light-and-dark mosaic mottling and hard, misshapen fruit with no defined spots — brown spot makes clear brown spots with rings and a yellow halo. A bacterial (greasy) spot looks wet, oily and angular, following the leaf veins, with no dry target rings; brown spot spots are dry and brown with rings. Sunburn or drought browns a leaf evenly but does not make sunken, girdling streaks on the stems or sunken pits on the fruit — those stem and fruit sores are the sure sign of brown spot.

from the stage when the vine is building its leafy framework along the wire (development), right through flowering (mid-season) and fruit fill (late season) — from then on there are always leaves and fruit for it to attack. Step up your checks the moment the weather turns warm, humid and wet (about 20–30 degrees C), with rain, heavy dew, or a dense, damp canopy, because that is when it explodes.

every week, walk a big "W" shape across the plot so you cross all four corners and the middle — not just the row nearest the path. Make about 10 stops along the way.

look over the tops and undersides of the leaves for the brown ring-marked spots, run your eye down the stems and the nodes for dark sunken streaks, and check the hanging fruit for sunken pits. Open up the dense, damp inside of the canopy — that still, wet air is where the disease starts before it shows on the outside.

the threshold is the very first spots — 1 spotted leaf, stem or fruit is enough to start protecting the crop, because the copper spray only shields healthy tissue and cannot cure a spot already there, so there is no safe waiting. And when warm, wet, humid weather is forecast to settle in, protect the vine before any spots appear rather than waiting to find them.

the moment you find spotted, girdled or dying-back shoots, prune them out and destroy them on a dry day so you don't spread wet spores by hand. Disinfect your knife or secateurs between vines — wipe with bleach or pass the blade through a flame — because dirty tools carry both this disease and the incurable woodiness virus from a sick vine to a healthy one. Never throw the diseased prunings on the compost or leave them lying in the plot.

at the very first spots, start a copper-based (protectant / contact) fungicide. "Protectant" means it coats the leaf and fruit surface and stops new spores getting in — it shields healthy tissue but cannot cure a spot already there, so it must go on at the first sign (or before spots in wet weather), cover the new growth, and be re-applied every 2–3 weeks through humid spells and after rain washes it off.

cover your skin, eyes, nose and mouth; spray in the cool of the morning or evening with the wind at your back; keep the spray off ripe fruit you will pick soon, off food, off drinking water and rivers, and away from children and bees. Respect the pre-harvest interval — the number of days the label says you must wait between the last spray and picking or selling the fruit. Wash yourself and your clothes afterwards.

don't lean on one product forever — rotate to a different chemical group each time (for example, alternate the copper with another registered protectant such as mancozeb) so the fungus can't get used to it. The open, airy canopy and the clearing of fallen leaves and fruit are the backbone; the spray only tops it up.

if the canopy is browning and dropping leaves even with spraying, prune hard to open the vine right up, cut out all the diseased and girdled wood well below the sore, and clear every fallen leaf and fruit from the ground so there is nothing to splash spores back up. Keep the protectant going on the fresh regrowth. Never carry spotted or rotting fruit into store — sort it out, because it will spoil the sound fruit around it.