Designing an effective trap cropping strategy: the effects of attraction, retention and plant spatial distribution

Abstract

Summary 1.Trap cropping, the use of alternative host plants to reduce pest damage to a focal cash crop or other managed plant population, can be a sustainable strategy for pest control, but in practice it has often failed to reach management goals. Of the few successful trap cropping examples at a commercial scale, nearly all have included supplemental management strategies that reduce pest dispersal off the trap crop. In contrast, the trap cropping literature has focused extensively on trap plant attractiveness. 2. To test whether the dispersal of insects off trap plants is as important as the anecdotal evidence suggests, we developed a simple model to understand how a trap plant's spatial configuration within a field, its attractiveness and its ability to retain pests affect pest density on a target cash crop. 3. The model predicts that when trap crop retention is low, trap cropping is ineffective, and small increases in retention offer little improvement. However, when retention is high, small differences in retention dramatically affect trap cropping efficacy. In contrast, when the attractiveness of a trap crop is high, further increases in attractiveness have little effect on trap cropping efficacy. 4. Placing trap plants close together is most often detrimental to pest management because it leaves large portions of the field without nearby traps. However, planting the trap crop in rows often does not clump the landscape enough to cause this detrimental effect. 5. Synthesis and applications. The predictions from our model confirm the anecdotal evidence that trap cropping failures may be attributed to a focus on attraction at the expense of retention. A very high retention rate is required for effective reduction of pest densities. Therefore, additional practices that prevent insects from dispersing back into the cash crop may be essential for effective trap cropping designs. These techniques include trap vacuuming, trap harvesting, sticky traps, planting a high proportion of trap plants or applications of pesticides or natural enemies to the trap crop.

Potential of Ethiopian mustard, Brassica carinata as a trap crop for large white butterfly, Pieris brassicae infesting Indian mustard, Brassica juncea

“…Therefore, need-based suppression of pest population in trap crop is required which further requires regular population monitoring. A number of techniques such as trap harvesting, trap vacuuming, sticky traps, pheromones, natural enemies, or pesticides have been used for pest population suppression in trap crop (Shelton and Badenes-Perez 2006;Holden et al 2012;Moreau and Isman 2012;Tillman and Cottrell 2012). Additional tactics could improve the effect of trap crop strips and targeted insecticide on resident pest populations, and bring about further reductions in pest population levels (Lin et al 2015).…”

Field margin vegetation enhances biological control and crop damage suppression from multiple pests in organic tomato fields

“…The control of within-field pest populations by concurrently diverting pests to trap-crops and enhancing populations of natural enemies has been coined biological control-assisted trap-cropping (Shelton & Badenes-Perez, 2006). Several other factors influence the effectiveness of this technique, including the attractiveness, within-field configuration, and the ability to retain pests of the trap-crop (Holden et al, 2012). The inclusion of floral supplements enhanced the parasitism rate of aphids, and reduced the rate of increase of foliar crop damage from Noctuidae and T. absoluta, with time.…”

Potential of pigeon pea as a trap crop for control of fruit worm infestation and damage to okra

“…Individual‐based models (i.e. spatially explicit models with a strong emphasis on individual behaviours) have been used to study the pest control efficacy of agro‐ecosystem diversification strategies as part of a theoretical approach (Potting et al ., ; Holden et al ., ). Individual‐based models are suitable research tools for studying the effects of interplay between the spatial distribution of trap plants, crop ecology (e.g.…”