Pests
Symptoms Tiny maggots inside ripe berries, with the fruit going soft and mushy. The adult is a small fly with a spot on each wing.Small white maggots inside ripe and ripening berries; fruit softens, collapses, and leaks when squeezed. The adult is a tiny vinegar-fly-like insect, the male with a dark spot near each wingtip. Fall-bearing and late crops are hit hardest. Cause An invasive fruit fly that lays eggs in good, ripe berries (not just rotten ones), and the maggots feed inside.Spotted-wing drosophila (Drosophila suzukii), an invasive vinegar fly whose females cut into healthy ripe fruit to lay eggs, unlike common fruit flies that use only rotting fruit. It is the major modern raspberry pest. Organic treatment Pick ripe berries every day or two and clean up any fallen or overripe ones (seal them in a bag, do not compost). Keep the planting open and airy. A cup of apple cider vinegar makes a simple monitoring trap.Harvest completely and often, every one to two days, so no ripe fruit is left on the cane, and remove and destroy overripe or fallen berries (bag them, do not compost). Open the canopy by pruning to reduce the cool, humid shelter the fly favors. Fine exclusion netting under 1 mm mesh and apple-cider-vinegar monitoring traps help. Prevention Grow earlier varieties when you can, keep the row narrow and clean, and pick often. Clear out wild brambles nearby.Choose early-ripening cultivars to dodge peak fly pressure, keep the planting narrow and open, and harvest on a tight schedule. Remove nearby wild brambles that host the fly.
Symptoms The tip of a new cane wilts and bends over, with two rings of tiny punctures just below it. A small beetle causes it.The tip of a primocane suddenly wilts and the top 6 inches droop, with two rings of punctures girdling the cane about an inch apart just below the wilted tip. A small long-horned beetle does the girdling; its larva tunnels down inside the cane. Cause A small beetle that girdles new cane tips and lays an egg there; the grub then tunnels down inside the cane.Raspberry cane borer (Oberea species), a slender black-and-yellow long-horned beetle. The female girdles the cane tip with two rows of punctures and lays an egg between them; the larva bores downward through the cane. Organic treatment As soon as a tip wilts, snip it off a few inches below the puncture rings and throw it away to remove the grub. Pick off any beetles you see.Cut and destroy each wilted tip a few inches below the lower ring of punctures as soon as you see it, removing the egg or young larva before it tunnels deep. Hand-pick the adult beetles. No spray is usually needed in a home planting. Prevention Check new cane tips in early summer and cut off any that wilt. Remove wild brambles nearby.Scout primocane tips through early summer and prune out wilted tips promptly; clean up wild brambles that harbor the beetle.
Symptoms Canes weaken, the leaves redden and wilt, and canes snap off at the base. The crown is tunneled inside. Plants slowly die.Whole canes weaken, leaves redden and wilt, and canes break off easily at the base; the crown and lower cane show tunneling and sawdust-like frass. Plants decline over two seasons and can die. A clearwing moth that mimics a yellowjacket is the adult. Cause A wasp-mimic moth whose grubs tunnel into the crown and base of the canes over two years, killing the plant from below.Raspberry crown borer (Pennisetia marginata), a clearwing moth whose larvae bore into the crown and lower canes over a two-year life cycle, destroying the base of the plant. Organic treatment Dig out and destroy badly infested plants, because the grubs are hidden inside the crown. Start new plantings with healthy plants on clean ground.Dig and destroy infested crowns, since the larvae are protected inside and hard to reach. Starting with clean nursery stock on a fresh site is the most effective control; keep plants vigorous so they outgrow light injury. Prevention Buy healthy plants, choose a spot with no old brambles, and dig out any plants that get infested.Plant certified, borer-free stock on ground without a recent bramble history, remove wild brambles nearby, and remove and destroy infested crowns to break the two-year cycle.
Symptoms Leaves chewed down to lace and berries nibbled, by shiny green-and-copper beetles that feed in groups on warm days.Leaves skeletonized to a lace of veins, and ripening berries chewed, often by clusters of metallic green-and-copper beetles feeding in the open on warm days from early to midsummer. Cause An introduced beetle whose adults eat the leaves and berries; its grubs live in lawns nearby.Japanese beetle (Popillia japonica), an introduced scarab whose adults feed on raspberry foliage and fruit; grubs develop in nearby turf. Organic treatment Knock the beetles into a jar of soapy water in the morning while they are slow. Do not use the bag traps, which attract even more. Net the fruit as it ripens.Hand-pick beetles into soapy water in the cool morning when they are sluggish, the most effective home control. Skip pheromone traps, which draw in more beetles than they catch. Protect ripening fruit with netting. Prevention Pick beetles off regularly while they are active, and keep plants healthy so they shrug off the damage.Keep plants vigorous, hand-pick consistently during the flight, and manage grubs in adjacent lawn areas if pressure is high.
Symptoms Tiny soft bugs on new shoots and under leaves, sometimes with sticky residue. The bigger risk is the viruses they spread.Small soft-bodied insects clustered on shoot tips and leaf undersides, sometimes curling new growth and leaving sticky honeydew. Their real danger is spreading raspberry mosaic and leaf-curl viruses, not the feeding itself. Cause Small sap-sucking insects whose main threat is carrying plant viruses from one raspberry to another.Several aphid species feed on raspberry sap; the large raspberry aphid in particular transmits the mosaic virus complex that causes incurable, crop-shortening decline. Organic treatment Spray them off with water, let ladybugs help, or use insecticidal soap if there are many. Do not over-fertilize.Knock light infestations off with a strong spray of water, support ladybugs and other natural enemies, and use insecticidal soap if needed. Avoid heavy nitrogen, which fuels the soft growth aphids prefer. Prevention Buy certified virus-free plants, pull out wild brambles and any sickly plants nearby, and encourage helpful bugs.Start with certified virus-free plants, remove nearby wild brambles and any virus-symptomatic plants, support beneficial insects, and avoid excess nitrogen.
Diseases
Symptoms Canes are weak, leaves yellow and wilt, and plants die in soggy spots. The roots are brown and rotten.Canes are weak and stunted, leaves yellow or scorch and wilt, and whole canes collapse, worst in low or poorly drained spots. Dug roots are brown to black and rotted, with a reddish-brown discoloration into the crown. Cause A soil disease that rots the roots when the soil stays too wet; the most common reason raspberry plantings fail.Soilborne Phytophthora water molds that attack roots in wet, poorly drained soil; the most damaging and common cause of raspberry decline, especially red raspberries on heavy ground. Organic treatment You cannot fix rotted roots, so it is all about drainage: plant on raised rows, keep water moving away, and replace dead plants on a drier spot.There is no cure once roots rot, so the response is drainage. Plant on tall raised beds or ridges, divert surface water, and replace dead plants with clean stock on a better-drained site. Prevention Plant on raised rows with good drainage, never let the soil stay soggy, and buy healthy plants.Plant only on well-drained ground or raised beds, choose more tolerant cultivars, never let raspberries sit in saturated soil, and start with disease-free plants.
Symptoms Small purple spots on the canes that grow into gray, sunken pits with purple edges, plus spots on the leaves.Small purplish spots on young canes that enlarge into gray-centered, purple-bordered pits; spots also appear on leaves and can crack the bark. Severe infections weaken canes and reduce yield, worst in wet springs. Cause A fungus that lives on old canes and infects new growth in wet weather, leaving sunken spots, worst on black raspberries.The fungus Elsinoe veneta (anthracnose), which overwinters on old canes and infects new growth during wet weather; black raspberries are especially susceptible. Organic treatment Cut out old and badly spotted canes, keep the planting open and airy, and water at the base, not over the leaves.Prune out and destroy old fruited canes and the most spotted primocanes, open the canopy for air movement, and avoid overhead watering. A dormant lime-sulfur application before bud break helps in bad cases. Prevention Use healthy plants, keep the row open, remove old canes yearly, and water low. Pick resistant varieties.Start with clean plants, keep rows narrow and open, prune out spent canes each year, and avoid wetting the foliage. Resistant cultivars reduce pressure.
Symptoms Dark cankers on the canes that make them wilt or snap, and brown patches at the leaf joints that weaken next year's fruiting side shoots.Cane blight: dark brown to purple cankers spread from pruning wounds, and canes wilt or die back above them, often snapping at the canker. Spur blight: brown-to-purple blotches at the leaf nodes of red raspberry that girdle the buds, so fruiting laterals are weak or fail next year. Cause Fungi that get into the canes through wounds and crowded growth, causing cankers and weak side shoots.Fungal canker pathogens (Leptosphaeria for cane blight, Didymella for spur blight) that enter through wounds and injured or crowded wood; both are worse in dense, wet, over-fertilized plantings. Organic treatment Cut out cankered canes well below the damage, clean your pruners between cuts, and thin the canes so air moves through.Prune out and destroy infected canes well below the canker, disinfecting tools between cuts, and thin canes for air movement. Avoid wounding canes and do not over-fertilize with nitrogen. Prevention Keep the row thin and airy, prune in dry weather, go easy on fertilizer, and remove old fruited canes right after harvest.Keep rows narrow and open, thin to the recommended cane density, prune only in dry weather, avoid excess nitrogen, and remove spent floricanes promptly after harvest.
Symptoms Weak, spindly new shoots in spring with bright orange powder coating the undersides of the leaves. The whole plant is infected for good.In spring, new shoots are spindly, pale, and bunchy, and the undersides of the leaves are covered with bright orange, powdery pustules. Affected plants never recover; the fungus is systemic in the whole plant. Cause A rust fungus that infects the whole plant for life, worst on black and purple raspberries and wild brambles.A systemic rust fungus (Arthuriomyces or Gymnoconia) that permanently infects the entire plant, most serious on black and purple raspberries and wild brambles. Organic treatment There is no fixing it. Dig up and destroy any plant showing the orange powder, roots and all, before it spreads. Pull out wild brambles nearby.There is no cure: dig out and destroy infected plants, roots and all, as soon as the orange pustules appear, before they shed spores onto healthy plants. Remove nearby wild brambles that carry it. Prevention Buy healthy plants, check new shoots each spring and remove any infected ones right away, and clear out wild brambles.Start with clean nursery stock, inspect new shoots each spring and rogue out any with orange rust immediately, remove wild brambles, and favor red raspberries (more resistant) over black where rust is common.
Symptoms Mottled, puckered leaves and a slow loss of vigor, with small crumbly berries that fall apart when you pick them. Plants only get worse.Leaves are mottled light and dark green, sometimes puckered or curled, and plants gradually stunt; berries become small, seedy, and crumbly, falling apart at picking. Decline worsens year over year with no recovery. Cause A group of viruses spread by aphids that infect the plant for good, carried in by aphids, infected plants, and wild brambles.A complex of aphid-transmitted viruses (raspberry mosaic) that permanently infect the plant; spread by the large raspberry aphid and carried in infected planting stock and wild brambles. Organic treatment There is no fixing a virused plant. Pull out and destroy any plant with mottled leaves and crumbly fruit, and keep aphids and wild brambles in check.There is no cure. Remove and destroy symptomatic plants promptly so they do not seed the aphids that spread it, and manage aphids and wild brambles around the planting. Prevention Start with certified virus-free plants, keep them away from wild brambles, control aphids, and replace an old declining patch with new plants on fresh ground.The whole defense is prevention: plant certified virus-free stock, site new plantings away from old or wild brambles, control aphids, and replace a declining patch on fresh ground rather than from your own suckers.
