Agronomy and phenology of “companion plants” of potential for enhancement of insect biological control

Abstract

Many insects which are useful as biocontrol agents feed on pollen and nectar as adults. Nectar and pollen sources (as “companion plants”) can be grown around or within crops to increase the density and diversity of predators and parasites. Plants vary in their suitability for such uses, however, and in this work, three cultivars of Coriandrum, two of Phacelia, and one each of Anethum and Fagopyrum were compared with respect to their sowing-to-flowering times, and susceptibility to low temperatures in Canterbury, New Zealand. There were large differences between cultivars with respect to sowing-to-flowering times. The time to flowering was the greatest with autumn sowings and Anethum was the most noticeably delayed. Fagopyrum failed to flower from March to July sowings, indicating a sensitivity to low temperatures or frosts; however, it had the shortest sowing-to-flowering period of all plants tested. The possibility of assessing other Fagopyrum cultivars for their tolerance to low temperatures and their ability to flower in early summer is discussed. © 1995 Taylor & Francis Group, LLC.