Diseases of beneficial insects

Nature

Diseases of insects are important when the insects concerned are beneficial to man. A diseased insect may be suffering from an infectious disease caused by a microorganism or a noninfectious disease, such as a metabolic disturbance, a genetic abnormality, a nutritional deficiency, a physical or chemical injury, or injury caused by predators or parasites.

Beneficial insects, for which diseases have important consequences for man, include those which produce useful products, such as the silkworm and the honeybee, and those which are predators or parasitic upon various pests. Until recently, concern has focused solely upon the infectious diseases of insects which produce useful products, such as pébrine, flacherie, polyhedroses and muscardine of the silk worm, and foulbrood and nosema of the honeybee. These and other diseases still cause losses to the respective industries. Recently increasing attention has been paid to noninfectious diseases of insects, especially those where injury is caused by chemical agents such as insecticides. Whole populations of honeybees have been wiped out by drifting insecticidal sprays. More disturbing are reports that efforts to kill pests have been more effective in killing their natural predators (either directly through poisoning with pesticides or indirectly through feeding on poisoned prey or through the disappearance of adequate prey), which may result in population explosions of pests, either when chemical control is relaxed or when the pest develops some type of immunity. Furthermore, pesticides applied to the soil indiscriminately destroy harmful and beneficial insects. The latter may be vital in the regeneration of the soil.

Background

The significance of diseases affecting beneficial insects, such as honeybees and silkworms, emerged in the late 19th century when widespread colony losses and crop failures were traced to pathogens like Nosema and foulbrood. Globalization and intensive agriculture have since amplified the spread and impact of these diseases, prompting international research collaborations and surveillance initiatives. Growing awareness of their ecological and economic roles has heightened concern, particularly as pollinator declines threaten food security worldwide.

Incidence

Outbreaks of diseases among beneficial insects, such as honeybees, silkworms, and bumblebees, have been reported on every continent where these species are cultivated or play a vital ecological role. The incidence of viral, bacterial, and fungal pathogens has increased in recent decades, threatening pollination services, silk production, and overall ecosystem health. Large-scale losses have been documented in both managed and wild populations, with significant economic and environmental repercussions.
In 2022, a severe outbreak of American foulbrood, a bacterial disease, devastated honeybee colonies in New Zealand’s North Island. The event led to the destruction of thousands of hives, severely impacting local apiculture and crop pollination.

Claim

Diseases of beneficial insects are a critical and urgent problem that threatens global food security, biodiversity, and ecosystem stability. Ignoring these diseases risks catastrophic declines in pollinators and natural pest controllers, directly endangering agriculture and natural habitats. Immediate research, funding, and action are essential to protect these vital species. The world cannot afford complacency—addressing diseases of beneficial insects must be a top priority for environmental and human well-being.

Counter-claim

Diseases of beneficial insects are vastly overblown as a concern. Nature has always balanced insect populations, and minor disease outbreaks rarely threaten their overall survival or ecosystem roles. Compared to pressing issues like habitat loss and pesticide use, worrying about insect diseases is a distraction. Resources should be focused on real threats, not on problems that nature is already equipped to handle. This topic simply does not warrant significant attention or alarm.