Greenhouses make it possible to garden year-round, irrespective of the seasons. Those identical greenhouse walls that erect a barrier to keep cold weather outside additionally create an environment that keeps pests inside. Properly identifying these pests is an important step in managing them and protecting your own plants. Incorrect identification may worsen the problem by inserting unnecessary costs and unnecessary work if you choose the incorrect treatment.
Greenhouse pest problems that go undetected are difficult to control. A regular monitoring program to enroll for undesirable insects is critical to successful pest management. Mount yellow sticky cards through your waterfront capture flying pests, like whiteflies and fungus gnats. The University of Connecticut recommends putting one to four sticky cards for every 1,000 feet of greenhouse space. For plants that tend toward thrips infestation, like herbs, blue sticky cards bring more pests. Press potato slices into plant growing networking to pull fungus gnat larvae. Check the traps weekly to determine whether pest populations require treatment.
Greenhouse pests change their appearance as they progress through a series of life stages. Some immature stages, like larvae, nymphs and instars, don’t resemble their more-recognizable adult types. Ladybug larvae, which resemble tiny alligators, look to the untrained eye like plant whales when, in fact, they mature into valuable adults that feed harmful aphids. Different pesticides are only successful on specific life stages so that it’s important to identify not only which pest you have, but also which stage. Otherwise, you’ll spend some time and money needlessly and control pests inadequately.
Adult phases of several pests move through a greenhouse by flying. Whiteflies, specifically the greenhouse and silverleaf types, are persistent and insidious visitors in enclosed greenhouses. Whiteflies feed plant cell sap and reproduce rapidly, with populations escalating rapidly to infestations. Fungus gnats also fly, but they do not hurt plants as their root-eating larvae do. Gnats are attracted to moist, humid conditions that are typical in greenhouses. Against yellow sticky cards, both of these pests appear in stark contrast to each other, with whiteflies, as their name suggests, coloured white, and fungus gnats seeming brown.
Many greenhouse pests are hard to find because they’re tiny crawlers. Aphids and mealybugs are soft-bodied insects that pierce plant tissue and siphon sap. Aphids often focuses on stems and leaf axils, which is where leaves meet stems. Mealybugs are distinguished by their white, cottony bodies that leap to nearby plants if disturbed. Spider mites are arachnids that look like dots moving across plant surfaces. They spin webs as defense against predators and not as snares to catch prey. Like aphids and mealybugs, spider mites feed on plant tissue and leave pinpoints of yellow stippling at each puncture wound. You’ll often detect their webbing before you see them.