Effectiveness of insecticide‐treated and non‐treated trap plants for the management of Frankliniella occidentalis (Thysanoptera: Thripidae) in greenhouse ornamentals

Abstract

The effectiveness of trap cropping as an integrated control strategy against western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), was explored in potted chrysanthemum, Dendranthema grandiflora (Tzvelev), greenhouse crops. The efficacy of flowering chrysanthemum trap plants, either treated with the insecticide spinosad or untreated, to regulate F. occidentalis populations was tested at different spatial scales (small cage, large cage and commercial greenhouse) and for different time periods (1 or 4 weeks). It was demonstrated that flowering chrysanthemums as trap plants lower the number of adult F. occidentalis in a vegetative chrysanthemum crop and, as a result, reduce crop damage. In the 4 week large-cage trial and the commercial trial, significant differences between the control and the trap plant treatments started to appear in the third week of the experiment. Larvae were only significantly reduced by the presence of trap plants in the 1 week small-cage trials. There were no significant differences between treatments with spinosad-treated and untreated trap plants in the number of F. occidentalis on the crop. This suggests that there was minimal movement of adult F. occidentalis back and forth between the trap plants and the crop to feed and oviposit. It is concluded that the trap plant strategy is a useful tool for integrated pest management against F. occidentalis in greenhouses.

Seasonal climatic variations influence the efficacy of predatory mites used for control of western flower thrips in greenhouse ornamental crops

“…(Gerson & Weintraub, 2007;Heinz et al, 2004;Yano, 2006). However, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), commonly known as western flower thrips (WFT), is the most important insect pest of greenhouse ornamental production (Buitenhuis et al, 2007;Heinz et al, 2004). Western flower thrips has the largest economic impact worldwide and has a host plant range of at least 244 plant species from 62 different plant families (Heinz et al, 2004).…”

“…Thrips have also been known to vector diseases to plants when feeding; most commonly Impatiens necrotic spot virus (INSV) and Tomato spotted wilt virus (TSWV), which further affect the plant value (Heinz et al, 2004). WFT are regarded as one of the most difficult insect pests to control due to their cryptic behaviour associated with oviposition, short development time, high fecundity, and rapid development of resistance to insecticides (Buitenhuis et al, 2007;Shipp et al, 2009). …”

“…Most techniques involve disruption of development through modifications to feeding and movement behaviours, modifications to food sources and, consequently, altered reproductive behaviours (Gerson & Weintraub, 2007;Pedigo & Rice, 2009 (Gerson & Weintraub, 2007;Pedigo & Rice, 2009), as well as plant breeding techniques to confer resistance to WFT or to make the plant less attractive (Heinz et al, 2004). Buitenhuis et al (2007) used "trap plants" in greenhouse chrysanthemum production systems as a means of distracting thrips from the actual crop. It was found that with the addition of flowering "trap" chrysanthemums in greenhouses, population numbers and damage were reduced on the crop.…”

“…It was found that with the addition of flowering "trap" chrysanthemums in greenhouses, population numbers and damage were reduced on the crop. The main benefit of this approach is that the pests are more concentrated in one area, not on the crop, where other means of reducing their population can be employed (Buitenhuis et al, 2007). Cultural control methods are only effective to a limited extent, and because ornamental production has a very low level of pest tolerance, other methods of control are often used in conjunction with cultural practices.…”

“…Many factors influence the ability of a BCA to effectively reduce pest populations in greenhouses. Often, cost effectiveness or rates of success of natural enemies are perceived barriers to successful biological control programs (Buitenhuis et al, 2007). Greenhouse conditions such as the physical and climatic environments, the crop plant, and other pest control practices can all affect the ability of a BCA to reduce pest populations (Heinz et al, 2004).…”