Occurrence and impact of golden dodder (cuscuta campestris yunker), invasion on species diversity of trees and shrubs in homa- bay county - Kenya

Abstract

C. campestris is a parasitic vine growing rapidly entwining and parasitizing on its host plants by inserting haustoria into the host plants’ stem and leaves. This study focused on the occurrence and impact of Cuscuta campestris on the diversity of host trees and shrubs in Homa-Bay County, Kenya. The overall objective was to investigate the occurrence and impact of Cuscuta campestris yunker, invasion on species diversity of trees and shrubs with specific objectives of the study as;1) To establish the occurrence and distribution of C. campestris invasion on trees and shrubs. 2)To determine the species diversity and characteristics of trees and shrubs parasitized by C. campestris. 3) To determine the effect of C. campestris on chlorophyll content and leaf biomass of infected host plants. The study was conducted in three Sub-counties, Rachuonyo North, Homa Bay town and Suba North Sub-counties. Descriptive Survey and Quasi Experimental Research Design were used. Purposive sampling technique was employed in selecting the study sites. Data was collected through laboratory analysis, structured interviews, questionnaires and field observations. Chlorophyll content was measured for both infected and uninfected plants using spectrophotometer while leaf biomass was measured for both dry and fresh weight of infected and uninfected samples. Data for climatic condition was obtained from National Meteorological Department - Homa Bay County Branch to show the variation in the occurrence and distribution of C. campestris on host plants with annual rainfall and temperature variability. Quantitative data was descriptively and inferentially analyzed in form of one-way ANOVA -SPSS-20. The study established that occurrence and distribution was more intense in shrubs, T. peruviana and E. tirucalli species than in host trees. Mean chlorophyll amounts were observed to decline from the uninfected to infected with chlorophyll a declining from 3.97 to 1.59 mg/g, b from 2.65 to 1.18 mg/g and total chlorophyll from 6.62 to 2.76 mg/g. Leaf biomass significantly decreased in infected host plants with mean fresh weight of 17.61g in infected significantly different, F (1, 4) = 235.74, p< .05, from the mean fresh weight of 24.23g in the uninfected while the mean dry weight of 5.55g in infected was significantly different, F (1, 4) = 159.72, p< .05, from mean dry weight of 7.87g in uninfected shrubs. The results demonstrated that C. campestris is detrimental to plant biodiversity. The study conclusions were, occurrence and distribution of C. campestris is less dependent on climatic variability but heavily dependent on host-plant, C. campestris has rich hostplant species diversity with wide range of characteristics from varied habitats and that Cuscuta has significantly affected leaf chlorophyll content and leaf biomass of infected host plants thus impose significant destruction on plant growth and loss of biodiversity. The study recommends substitution of preferred host plants with hardly infected plants, sensitizing of residents on the impacts for the need to design appropriate sustainable management protocol and legislation to classify the weed as noxious plant in Kenya. Further research to focus on determining the nutrient composition in preferred host plants to enable further understanding for effective management.