Invasive Cruel Plant

March 28, 2014


Photographer: Menashe Davidson
Summary Author: Menashe Davidson

Shown above is an invasive plant known as the Cruel Plant (Araujia sericifera) smothering a mandarin tree in a citrus plantation on the Sharon plain of Israel. This woody evergreen vine, native to South America, is indeed cruel to orchard trees and other plants of the Middle East. InvasivePodThe International Union for Conservation of Nature, (IUCN) describes invasive species as “animals, plants or other organisms introduced by man into places out of their natural range of distribution, where they become established and disperse, generating a negative impact on the local ecosystem and species.” They can exhibit fast growth, rapid reproduction, high dispersal ability and tolerance to a wide range of environmental conditions. In addition, they can thrive in close association with other organisms.

A. sericifera does quite well in the wet soil that's found in irrigated citrus plantations. It produces large quantities of black seeds in pear-shaped pods about 3 – 4 in (8 – 10 cm) long (see photo at left). The seeds are viable for at least 5 years as they await appropriate moisture conditions to germinate. Silky hairs allow the seeds to be dispersed by the wind.

The cruel plant's fast-growing vines can cover a tree canopy 10 ft (3 m) high in two or three years, competing with the tree for light, water and nutrients. Eradication of this pest is very laborious as the vines are removed by hand. Photos taken on July 28, 2013.

Photo Details: Top - Camera: Apple iPhone 5; Focal Length: 4.1mm (35mm equivalent: 33mm); Aperture: f/2.4; Exposure Time: 0.0015 s (1/653); ISO equiv: 50. Inset - Same except: Exposure Time: 0.0083 s (1/120); Software: Microsoft Windows Photo Viewer 6.1.7600.16385.