Abstract:
Cuscuta sp. is a familiarized medicinal plant for centuries but at times it has been reported parasitizing economically
important crops like onion (Allium cepa L.) and chilli (Capsicum annum L). Due to the risk posed by this holoparasitic
weed on cultivated crops, a field based research study was carried out with the objective of measuring parasitic
potentiality of Cuscuta sp. through identifying minimum length of infective unit as tendrikand its host searching
ability, estimating biomass loss of A cepa and screening of host range with selected vegetable crops and medicinal
plants. Treatments were set up to measure the parasitic potential of Cuscuta sp. on different ages of A cepa at two
weeks and four weeks. Results revealed that minimum of five cm long Cuscuta tendril have the capability to initiate
infection. Its tendrils have the potential to grow towards its host, A. cepa up to 60 cm distance. Therefore, spacing
between two adjacent A cepa plots more than 60cm can be practicable to reduce the spreading of Cuscuta sp. At the
time of harvesting, biomass loss of leaves and bulbs in two and four weeks old parasitized A. cepa were 58.4%, 14.5%
and 89.1%, 46%, respectively. Dry weights of Cuscuta sp. were not significantly different at all the weeks. Number of
leaves, shoot/root length ratio except number of bulbs, were significantly differed with age of A. cepa. Only two weeks
old parasitized A. cepa yielded small size bulbs. Parasitic potential of Cuscuta sp. was not depend on the age of A. cepa.
Results of host-parasite interactions showed that Brassica oleraceae and Raphanus sativus were the non-host crops of
Cuscuta sp. Intercropping and crop rotation with non-host crops are the best alternatives in the crop fields suspected
with infection of Cuscuta spp.
