Issai hardy kiwi vines

Kiwifruit black rot, caused by *Botryosphaeria dothidea* — distinct from brassica black rot and grape black rot. In the field, it shows as leaf spots, shoot blight, dieback, and stem cankers. The same pathogen later causes ripe rot and soft rot during fruit storage. The fungus overwinters in pycnidia and pseudothecia (resting structures) on kiwifruit shoots and orchard debris.

Triggers: Favored by warm humid weather, surface wetness, and high humidity. Spores germinate and infect with several hours of standing water on shoots, leaves, and fruit. Primary inoculum comes from overwintered structures on infected wood, with secondary spread during the growing season.

On Issai Hardy Kiwi: Dense growth and humid weather favor fungal disease.

Prevention: Prune for airflow, mulch, and avoid overhead irrigation.

Risk fades when: Spore germination and infection require free water. Sustained dry conditions reduce new field infection, but existing cankers persist.

A seedling killer caused by several different fungi working together. It hits vegetables, flowers, herbs, microgreens, and cover-crop seedlings the same way — seeds rot before they emerge, or young seedlings collapse right at the soil line. Wet seed-starting mix and poor airflow in seedling trays are the classic conditions.

Triggers: Wet soil or starting mix, poor drainage, seedlings packed too tightly, contaminated trays or media, and stagnant air all favor damping-off.

Risk fades when: Drying the soil surface and improving airflow slows new spread. Collapsed seedlings don't recover, but the rest of the tray can be saved.

A water mold (not a true fungus) that attacks roots and crowns in waterlogged soil. It's most dangerous in heavy, poorly drained soil after extended rain — basically any time water sits around plant roots for days.

Triggers: Pythium infects from 50-95°F as long as the soil stays saturated. Phytophthora capsici is most active at 75-85°F. What matters most is how long the soil stays waterlogged, not just whether it rained.

Risk fades when: Risk fades when soil returns to field capacity (normal drained moisture). How long that takes depends on your soil — sand drains in hours, clay can take days.

A soil-borne fungus that gets into roots and clogs the plant's water plumbing, causing yellowing, wilt, and slow decline. Unlike Fusarium, Verticillium tolerates cooler soils — symptoms often show up in late spring before the soil really warms. The fungus has a huge host range (over 200 plant species including tomato, pepper, eggplant, strawberry, mint, and many ornamentals) and survives in soil as tiny structures called microsclerotia for 10+ years. Yellowing is usually more uniform across the plant than Fusarium's signature one-sided pattern. Cool weather pathogen — soil temperatures of 70-80°F are ideal, and infections often slow in mid-summer heat.

Triggers: Cool-soil pathogen, active at 70-80°F soil temperatures. Symptoms often appear in late spring or early summer before soil warms past 85°F. Activity slows in mid-summer heat.

Risk fades when: Activity slows when soils warm above 85°F. The seasonal pressure fades, but the pathogen itself persists in soil for 10+ years.

Aphids are soft-bodied sap-sucking insects that cluster on tender new growth. Most established plants tolerate moderate populations and will outgrow damage on their own, but aphids are the most important plant virus vectors in the garden, transmitting more than 100 plant viruses including potato leafroll, cucumber mosaic, and turnip mosaic. Honeydew excreted while feeding supports sooty mold growth and attracts ants that protect aphids from natural enemies.

Triggers: Optimal development at ~75°F (green peach aphid) per UC IPM Floriculture; melon aphid develops fastest above 75°F. Many species heat-intolerant above 90°F and crash in mid-summer. Soft new growth and over-fertilization with high N favor population buildup. Females give live birth parthenogenetically most of growing season — one generation in ~1 week under optimal conditions.

Risk fades when: Per UC IPM and Clemson HGIC, populations crash in mid-summer heat (>90°F) for many species, return in cooler conditions

Birds cause significant damage to ripening fruit (berries, grapes, figs, cherries), to newly-planted seeds, and to seedlings. Damage peaks during fruit ripening on berries and during seed-head ripening on sunflowers. Robins feed low on bushes; starlings feed in upper canopy; species and feeding patterns vary widely. Even partial damage opens entry points for diseases and insects.

Triggers: Damage seasonal — peak during fruit ripening (June-August in north). Dry years intensify damage as birds use fruit for water. Proximity to forest edges or harvested grain fields amplifies pressure.

On Issai Hardy Kiwi: Ripening fruit attracts birds quickly.

Prevention: Net shrubs or vines before the crop colors.

Risk fades when: Risk is tied to each crop's ripening window - berries in June through August, corn at silking, sunflower at seed-head fill - so pressure fades once the vulnerable fruit or grain is harvested; netting or row cover during that specific window is the main protection (Oregon State Extension, EM 9286).

Fuzzy gray mold on flowers, fruit, and wounded tissue. It thrives in cool, humid, enclosed spaces — University of Minnesota notes this is unlikely to be a problem in open home gardens and rare even in field tomatoes. It's mostly a greenhouse and high-tunnel concern, included here because SoilStack supports those growing environments.

Triggers: Develops at 60-75°F with humidity above 80%. Infection requires 4-6 hours of standing water on the plant tissue. UMN's data shows it's unlikely in open home gardens.

Risk fades when: Temperatures above 82°F suppress growth and spore production. That's the published threshold.

Japanese beetle adults feed gregariously on the foliage and flowers of more than 300 host species, skeletonizing leaves by chewing tissue between the veins. Larvae (white C-shaped grubs) damage turf and root systems. Adults are active during the warmest part of sunny summer days, when populations can rapidly defoliate roses, grapes, and ornamentals. Do not use Japanese beetle traps near plants — the lures attract more beetles than they catch.

Triggers: One generation per year. Overwinters as larva in soil. Adults emerge late June-early July (peak July). Adults active during warmest part of sunny days. Females lay 40-60 eggs in turf 3 inches deep.

Risk fades when: One generation per year: adult emergence peaks around early August and tapers to the last beetle by about September 1, so above-ground feeding pressure ends in early fall as the adults die off and grubs move underground (UMass Extension, UMN Extension).

Microscopic soil-dwelling roundworms that burrow into plant roots and cause swollen knots (galls). Above ground, the plant looks stunted, yellowed, and wilted even with plenty of water. They attack over 2,000 plant species, so almost nothing is safe. They're most active in warm soil (70-85°F) and do more damage in sandy soils, where they move easily. Once a bed has them, populations stick around for years.

Triggers: Soil temperatures of 70-85°F are ideal for them; below 60°F they go dormant. Sandy soils make it easy for them to move and reproduce, while heavy clay slows them down considerably. In warm soil, a full generation completes in about 27 days.

Risk fades when: Activity drops sharply once soil cools below 60°F. Damage stops accumulating for the season, but the population stays in the soil and returns when warmth does.

Scales are immobile sap-sucking insects under protective waxy or hardened covers. Soft scales produce sticky honeydew that supports sooty mold; armored scales cause direct dieback. They are primarily pests of woody plants and perennial herbs — fruit trees, berries, citrus, bay, rosemary — rather than annual vegetables. Females are sedentary as adults; the mobile 'crawler' stage that hatches in late spring/early summer is the target for control.

Triggers: Most species: one generation/year in north; multiple in south. Lecanium overwinters as 2nd-instar nymphs on twigs; crawlers emerge June-July. San Jose scale overwinters as 2nd instar on bark; crawlers May-June. Stressed plants more susceptible; ant attendance protects scales by deterring parasitic wasps.

Risk fades when: The vulnerable stage is the mobile crawler, which appears in a narrow late-spring to early-summer window depending on species; once crawlers settle and form their protective covering, sprays are far less effective, so the treatable risk window closes after crawler emergence (Penn State Extension, UMN Extension).