Control of cocoa mirids using aqueous extracts of Thevetia peruviana and Azadirachta indica

Figures & data

Table 1. Average number of mirids per treatment and per site before and after application of the aqueous extracts during the 2013 and 2014 cacao seasons

Sites	Year	Treatments	Pre treatment population* mean±se	Post treatment population ** mean±se
Biakoa	2013	TP	5.33 ± 0.33	1.21 ± 0.11
		AI	5.67 ± 0.99	1.98 ± 0.14
		Actara	4.83 ± 0.70	1.67 ± 0.13
		Water	6.33 ± 1.14	8.95 ± 1.18
	2014	TP	2.00 ± 0.26	0.78 ± 0.09
		AI	2.50 ± 0.34	1.1.35 ± 0.18
		Actara	1.50 ± 0.43	0.65 ± 0.07
		Water	3.00 ± 0.45	4.38 ± 0.23
Bidambogo	2013	TP	0.33 ± 0.21	1.19 ± 0.12
		AI	0.33 ± 0.21	2.02 ± 0.06
		Actara	1.67 ± 0.67	0.83 ± 0.17
		Water	2.00 ± 0.73	7.31 ± 1.67
	2014	TP	2.00 ± 0.26	0.26 ± 0.32
		AI	2.17 ± 0.17	0.90 ±0.10
		Actara	1.67 ± 0.21	0.21 ± 0.04
		Water	2.50 ± 0.34	3.15 ± 0.03

Note: Mean values were obtained from 45 trees per plantation (15 trees * 3 blocks).

* Mean values of mirids two weeks before the treatment.

** Mean values of mirids over the whole monitoring period after treatment.

Figure 1. Effect on the mirid mortality rate of aqueous extracts of T. peruviana and A. indica applied directly on mirid bugs.

Notes: TP 10%: 10% aqueous extract of T. peruviana, TP 25%: 25% aqueous extract of T. peruviana; AI 10% and AI 25%: 10% and 25% aqueous extract of A. indica.

Figure 2. Effect on the number of pod lesions of aqueous extracts of T. peruviana and A. indica applied directly on mirid bugs for two periods (one to three days and four to six days post direct application). Different letters refer to significant differences (Wilcoxon test, p < 0.05).

Figure 3. Effect on pod lesions of aqueous extracts of T. peruviana and A. indica applied to pods (residue toxicity).

Notes: *Refers to a significant difference in the mean number of bites between pods treated with extracts and pods treated with water (Wilcoxon test, *p < 0.05; **p < 0.01, ***p < 0.001). Different letters refer to significant differences between the pods treated with the extracts.

Table 2. Results of the summary of the linear mixed model used to explain the significant effect of treatment on the mean population of mirids over the monitoring period

Model:
Post-treatment population ~ Treatment + (1|Site:Block) + (1|Year) + (1|Before treatment population)
Fixed effects	Estimate	Std. error	t value
Intercept	5.9464	0.8988	6.616
Treatment-AI	−4.3829	0.4894	−8.956
Treatment-TP	−5.0833	0.4894	−10.387
Treatment-Actara	−5.1071	0.4894	−10.435