Tree Diversity and Damage by Cypress Aphid, Cinara cupressi, on Juniperus procera in Gulele Botanical Garden and Entoto

Table 1

Mean aphid nymph and adult densities per twig at Entoto and GBG in mixed and sole plantations.

Site	Planting system	Whorl	Mean no. of nymph	Mean no. of adults	t value	value
Entoto	Mixed	Lower	1.63	2.38	0.848	0.40
		Middle	2.13	3.63	1.30	0.21
		Top	1.56	2.44	0.98	0.34
	Sole	Lower	4.00	2.69	1.183	0.25
		Middle	5.25	2.94	1.94	0.03
		Top	3.38	4.06	0.50	0.62
GBG	Mixed	Lower	0.94	3.19	2.69	0.014
		Middle	0.31	3.44	3.99	0.001
		Top	0.19	2.44	2.65	0.018
	Sole	Lower	4.25	3.69	0.42	0.68
		Middle	2.75	3.69	1.18	0.88
		Top	2.81	4.50	1.65	0.11

Statistical significance at α = 0.05.