Lesson 67: Not a Disease
Problems that look alarming but aren't caused by germs or parasites, and how to prevent them
Some of the most common colony problems have nothing to do with disease. They come from cold, hunger, heat, or the queen. They matter because they kill colonies just as surely as a disease, because some of them look like disease, and because they're usually preventable with good management.
Chilled brood
What it is: brood that died from cold because there weren't enough bees to keep it warm.
When it happens: - When temperatures drop suddenly and the bees pull into a tighter cluster, leaving brood at the edges uncovered. - In spring build-up, when the queen lays more eggs than the (winter-reduced) workforce can cover. - When a beekeeper leaves brood frames out of the hive too long on a cold day, or spreads the brood nest too early (lesson 33).
How it looks: - Dead brood at the edges and lower parts of the brood area, where the cluster couldn't reach. - Instead of pearly white, larvae are yellowish-white to brown, sometimes with black edges on their segments; some may be dark all over. - Sometimes perforated cappings over dead sealed brood. - All stages can be affected, in a patch, rather than scattered here and there.
Chilled brood can look like European foulbrood (lesson 59), but it doesn't rope (lesson 58). The bees will clean it out.
Prevention: keep colonies strong, don't open hives or leave frames out for long in cold weather, and don't split or spread brood in cool spring weather.
How it looks:
Chilled brood: dead larvae turned dark in a patch of cells.
Starvation
Starvation is one of the leading causes of colony death over winter, and it can happen any time of year when there's no nectar coming in.
How it happens: - The colony goes into winter without enough stored honey. - The cluster moves away from its honey, or can't reach it in very cold weather, and starves with honey just inches away. - A long dearth (no flowers) in summer or fall, or a cold, wet spring when the colony is raising lots of brood.
How it looks: many dead bees head-first in the cells, dead bees between the combs and piled on the floor, and no honey near the cluster (or none at all).
Prevention: - Heft the hive (lift the back) regularly to judge stores; a light hive needs feeding (lessons 39 and 52). - Feed heavy (2:1) syrup in fall if stores are low, using a feeder inside or on top of the hive. Entrance (Boardman) feeders don't work in cold weather, because bees can't leave the cluster to reach them. - Know how much honey your colony needs for winter. It depends on your region; your Seasonal Guide gives the number for your area. - In late winter, give emergency sugar (dry sugar or fondant/candy) directly above the cluster if a colony is light.
Overheating
Bees are very good at cooling their hive, as long as they can fan, collect water and move around. They overheat when they can't: - when confined in a closed hive in hot weather, especially while being moved (lesson 28); - when there's no water nearby (lesson 51).
Signs: bees crawling rapidly and fluttering their wings; when released, they scatter by crawling. Bees killed by heat may look wet, from fluids they brought up trying to cool themselves. Overheating usually starts above about 100°F inside.
Prevention: move bees in the cool of the evening, don't keep them shut in for long on hot days, give plenty of ventilation (screens) when moving, and keep water available. In very hot areas, afternoon shade helps (lesson 24).
Comb can also melt in extreme heat, especially new comb in a hive in full sun with poor ventilation.
Spotty brood
A spotty brood pattern (lots of empty cells scattered through the capped brood) is a symptom, not a disease. It can mean: - a failing or poorly mated queen (lesson 42), who lays haphazardly, and may lay drone brood (raised, bullet-shaped cappings) mixed with worker brood; - inbreeding: many larvae are removed because they'd have developed as diploid drones; - disease: AFB, EFB, chalkbrood or sacbrood (lessons 58–60), where bees remove sick larvae; - varroa mites: parasitic mite syndrome (lesson 62); - queenlessness or laying workers (lessons 43–44); - chilled brood or a dearth, which cause bees to raise less brood.
What to do: look closely: check the dead or sick brood for disease signs, count mites, and check for eggs, a queen and her laying pattern. If disease and mites are ruled out, requeen (lesson 45).
What to remember
- Chilled brood: dead brood at the edges of the brood nest after cold snaps or in spring build-up; looks like EFB but doesn't rope.
- Starvation: bees head-first in cells; prevent by hefting, feeding 2:1, and knowing your region's winter needs.
- Overheating: from confinement and no water; move bees in the evening with ventilation.
- Spotty brood is a symptom: check disease, mites, queen; often the fix is requeening.
Quick check
- Where in the brood nest is chilled brood usually found?
- You find a dead colony with many bees head-first in cells and no honey nearby. What happened?
- Name three possible causes of a spotty brood pattern.
Show answers
1. At the edges and lower parts of the brood area, where the cluster couldn't cover it. 2. It starved. 3. Any three of: a failing or poorly mated queen; inbreeding; brood disease; varroa mites; queenlessness or laying workers; chilled brood.
Adapted from: UGA Bee Program, Honey Bee Disorders: Non-infectious Diseases and Pests; Penn State Extension, A Quick Reference Guide to Honey Bee Parasites, Pests, Predators, and Diseases; Honey Bee Health Coalition, Identifying and Mitigating Foulbrood (2022); Penn State Extension, An Organic Management System for Honey Bees.
Photo: Chilled brood, Apiculture Extension Educators of America (AEEA), CC BY 2.0, via Flickr.
Adapted from university Extension sources. Experienced Georgia beekeepers are reviewing these lessons. See something that doesn't match your experience? Tell us.