egg hatchability of Globodera rostochinensis when treated
with a combination of T. erecta leaf and root extracts. This
may have been due to the effect of several bacterial
endophytes, Microbacterium esteraromaticum and Kocuria
varians, recently isolated from Tagetes spp. by Sturz and
Kimpinski (2004) which were shown to depress population
densities of P. penetrans, when introduced into potato,
Solanum tuberosum. Whichever mode of action predominated in the current study the method of extraction of
active principles from T. erecta was designed to ensure that
both chemicals and microorganisms were unaffected by the
extraction process.
Interestingly, juvenile M. incognita populations were
suppressed more by extracts prepared from stem and whole
plants rather than root portions (Siddiqui and Alam, 1988)
suggesting that extracts could be prepared from residual T.
erecta plant material grown by commercial flower producers without L. esculentum farmers compromising yield by
intercropping. Alternatively resource-poor farmers could
grow T. erecta on bunds or uncultivated land and prepare
extracts from plant material by pruning when required.