Date of Award


Document Type

Honors Thesis



First Advisor

Robert Zdor


Rhizobium rubi AT3-4RS/6 and tryptophan may be useful in replacing chemical herbicides as biological control agents (Kennedy et al., 1990). Previous research has shown that Rhizobium rubi AT3-4RS/6 produces IAA-like compounds that are deleterious to weed growth. In this project R. rubi AT3-4RS/6 will be formulated in Celite, a granular, diatomaceous earth carrier. The purpose of this research is to analyze if tryptophan influences R. rubi AT3-4RS/6 populations in the velveltleaf rhizosphere, and if this colonization is associated with reduced root weight and shoot length. The experiment design consists of five soil treatments (bacteria+tryptophan+celite, tryptophan+celite, bacteria+celite, celite alone, and soil alone) with 10 velvetleaf plants each. The decreasing trend of the root weights, shoot lengths, and bacterial colony counts of the trptophan and R. rubi AT3-4RS/6 treatments will be recorded and analyzed using two statistical tests (t-test, and ANOVA). The results showed that for all three independent trials there was significant variance of the shoot lengths and root weights. And the average bacterial population of both trials for the tryptophan and non-tryptophan treatment was 1.26 x 1010 cfu/g dry root and 1.02 x1011 cfu/g dry root respectively.

Subject Area

Chondrodendron tomentosum., Tryptophan., Weeds--Control.