ABSTRACT
Rose flower is the world’s most traded cut-flower with 74% of it coming from
Kenya. Kenya has potential for higher rose production if challenges of pests and
diseases are dealt with. Pests like spidermites, false codling moth, caterpillars,
aphids, thrips, nematodes and diseases such as crown gall, downy mildew, powdery
mildew and botrytis highly compromise production. Crown gall disease, caused by
Agrobacterium tumefaciens is the most problematic disease of roses in Kenya and
causes a production loss of up to 60% depending on age and variety. This study
evaluated the prevalence of crown gall disease and management of the disease using
Zingiber officinale rhizome and Artemisia annua leaves extracts, in an effort to
replace conventional chemicals due to their environmental and economic cost.
Survey of selected flower farms in Kenyan showed a crown gall prevalence ranging
from 0.1% to 65%. Zingiber officinale and Artemisia annua phytochemical
screening indicated presence of terpenoids, flavonoids, alkaloids, saponins,
glycosides, phenols and tannins. Agrobacterium tumefaciens colonies used in testing
antibacterial effect of the extracts were isolated from crushed crown galls and
purified through their growth in Congo red YEMA medium and yeast peptone
glucose agar. The colonies were authenticated biochemically by Gram staining,
motility test, citrate utilization, catalase production, urease production and
ketolactose test. Antibacterial effect of the extracts were determined by measuring
the diameter of the inhibitory zone around the filter discs soaked in extracts on
Agrobacterium tumefaciens inoculated media. Micro-dilution technique on
microtiter plate was used to determine the minimum inhibitory concentrations of the
plant extracts used in soaking the filter discs. Artemisia annua, Zingiber officinale,
mixture of Zingiber officinale and Artemisia annua had Minimum inhibitory
concentration of 125mg/ml, 62.5mg/ml and 31.25mg/ml respectively. The
recommended rate (6.25 ml/l) of copper hydroxide was used. Copper hydroxide and
Artemisia annua had antibacterial inhibitory zone of 12.8mm. This zone was
significantly different from that of Zingiber officinale and mixture of Zingiber
officinale and Artemisia annua which was 10.6 and 10.2 mm respectively (P ≤0.05).
The research therefore revealed that Artemisia annua and copper hydroxide
inhibited bacterial growth better than Zingiber officinale and mixture of Zingiber
officinale and Artemisia annua. Results of treatments done on inoculated rose plants
in the greenhouse in terms number of plants with galls, gall weight and stem length
showed similar tread to in vitro bacterial growth inhibition. The ultimate stem length
of Artemisia annua and copper hydroxide treatment were 69.4cm and 65.8cm
respectively. These lengths were better and significantly different from that of
Zingiber officinale and mixture of Artemisia annua and Zingiber officinale which
were 48.8cm and 54.4cm respectively (P ≤0.05). From the results of this research,
Artemisia annua and Zingiber officinale extracts are promising biocontrols for
crown gall in roses. Farmers are recommended to continue with integrated crown
gall control methods and pursue plant extracts as an alternative. The performance of
Artemisia annua extracts compared well with that of conventional copper hydroxide and is therefore the better option.
KARIUKI, N (2021). Management Of Crown Gall Disease In Selected Rosa Hybrida Farms In Kenya Using Artemisia Annua Leaves And Zingiber Officinale Rhizome Extracts. Afribary. Retrieved from https://afribary.com/works/management-of-crown-gall-disease-in-selected-rosa-hybrida-farms-in-kenya-using-artemisia-annua-leaves-and-zingiber-officinale-rhizome-extracts
KARIUKI, NJAGI "Management Of Crown Gall Disease In Selected Rosa Hybrida Farms In Kenya Using Artemisia Annua Leaves And Zingiber Officinale Rhizome Extracts" Afribary. Afribary, 26 May. 2021, https://afribary.com/works/management-of-crown-gall-disease-in-selected-rosa-hybrida-farms-in-kenya-using-artemisia-annua-leaves-and-zingiber-officinale-rhizome-extracts. Accessed 08 Oct. 2024.
KARIUKI, NJAGI . "Management Of Crown Gall Disease In Selected Rosa Hybrida Farms In Kenya Using Artemisia Annua Leaves And Zingiber Officinale Rhizome Extracts". Afribary, Afribary, 26 May. 2021. Web. 08 Oct. 2024. < https://afribary.com/works/management-of-crown-gall-disease-in-selected-rosa-hybrida-farms-in-kenya-using-artemisia-annua-leaves-and-zingiber-officinale-rhizome-extracts >.
KARIUKI, NJAGI . "Management Of Crown Gall Disease In Selected Rosa Hybrida Farms In Kenya Using Artemisia Annua Leaves And Zingiber Officinale Rhizome Extracts" Afribary (2021). Accessed October 08, 2024. https://afribary.com/works/management-of-crown-gall-disease-in-selected-rosa-hybrida-farms-in-kenya-using-artemisia-annua-leaves-and-zingiber-officinale-rhizome-extracts