ABSTRACT
Pest management in greenhouses is a challenge primarily due to the conditions that are associated with growing many different types of horticultural crops and the multitude of insect and mite pests that are encountered during production. First, always correctly identify insect and/or mite pests, so the appropriate pest management strategies are implemented. Furthermore, be sure to thoroughly understand the life cycle, biology, and behavior of insect and mite pests in order to target the most susceptible life stages (larvae, nymphs, and adults). In order to alleviate problems with insect and mite pests, a variety of pest management strategies should be implemented, including scouting, cultural control and sanitation, physical control, pesticides, and biological control. Cultural control and sanitation practices are the “first line of defense” in alleviating problems with insect and mite pests, which includes proper irrigation and fertility, and removing weeds from both inside and outside the greenhouse. Scouting provides information on the population dynamics based on the numbers of insect and mite pests present at any given time during the growing season. The use of physical methods to exclude insect pests by installing microscreening will help prevent insect pests from migrating into the greenhouse from
outside, which will also alleviate any problems with viruses vectored by certain insect pests such as the western flower thrips. Although there may be a substantial initial financial investment associated with installing microscreening, overall, the long-term benefits will result in a cost savings based on reduced pest problems and decreased pesticide inputs. There are different types of pesticides used in greenhouse production systems including contact, stomach poison, translaminar, and systemic. Some are broad spectrum in regards to activity, whereas others are narrow spectrum. The use of pesticides in greenhouses can be effective in suppressing insect and mite pest populations if they are applied appropriately, which includes timing of applications, coverage of all plant parts, and conducting applications at frequent enough intervals to insure high mortality of the susceptible life stages of a given insect or mite pest. There are a number of factors that can contribute to insufficient performance of a pesticide, including incorrect pest identification, poor water quality, extended shelf life, and using the inappropriate label rate. Furthermore, in order to mitigate resistance, always rotate pesticides with different modes of action. Biological control involves the release of natural enemies, including parasitoids, predators, and/or applying entomopathogenic nematodes. The use of biological control will only be effective if natural enemies are released preventatively, that is, before insect or mite pest populations reach outbreak proportions. Also, always conduct quality control assessments in order to determine the viability of natural enemies purchased from suppliers/distributors. Moreover, understand that the performance of natural enemies may be influenced by environmental conditions (e.g., temperature, light intensity, photoperiod, and relative humidity) and plant types.
