Appendix A. Validation of the method for the assessment of the number of coffee berries bored by Hypothenemus hampei.
In each study plot, the total number of bored berries per coffee bush was estimated in five selected coffee bushes by counting the number of bored coffee berries (BCB) on a sample of four fruiting branches in four stories per coffee bush, and the total number of fruiting branches (FB) per coffee bush.
Estimated number of bored berries = (FB × BCB/4).
We validated this method by counting the total number of bored coffee berries per branch in all the fruiting branches of 20 coffee bushes. The number of bored coffee berries and the number of fruiting branches per coffee bush ranged 24–794 (Table A1) and 18–118, respectively. Then, these coffee bushes were assembled into 32 unique groups of five bushes to include a wide range of bored coffee berries per group. Each coffee bush belonged to eight groups only (Table A1). We randomly selected (eight times) four branches per coffee bush (one per story) allowing us to calculate eight values of BCB per coffee bush (one for each group to which each coffee bush belonged). In each group, the estimated number of bored coffee berries per coffee bush was deduced. The correlation between the number of bored coffee fruits estimated per coffee bush and the exact number of bored coffee fruits was calculated. We found a very significant relationship (r2 = 0.86; P < 0.01) indicating our method was both robust and reliable (Fig. A1).
TABLE A1. Coffee bush distribution into the 32 groups used for the validation of the coffee berry borer sampling method.
Coffee bush number† |
Number of bored |
Group numbers† to which each |
1 |
24 |
1-7-10-17-18-24-27-31 |
2 |
25 |
1-2-8-10-13-18-24-27 |
3 |
34 |
1-2-3-7-10-18-24-25 |
4 |
43 |
1-2-3-4-8-10-18-20 |
5 |
45 |
1-2-3-4-5-13-15-22 |
6 |
45 |
2-3-4-5-6-15-20-22 |
7 |
82 |
3-4-5-6-8-9-13-15 |
8 |
109 |
4-5-6-8-9-11-15-20 |
9 |
114 |
5-6-7-9-11-12-17-19 |
10 |
115 |
6-9-11-12-13-14-19-22 |
11 |
119 |
9-11-12-14-16-19-25-28 |
12 |
128 |
7-11-12-14-16-17-19-21 |
13 |
172 |
12-14-16-17-21-23-28-29 |
14 |
187 |
7-14-16-21-23-25-26-29 |
15 |
238 |
8-16-20-21-23-26-29-30 |
16 |
374 |
15-21-23-25-26-28-30-32 |
17 |
418 |
10-13-22-23-26-30-31-32 |
18 |
480 |
17-19-26-27-28-30-31-32 |
19 |
587 |
20-22-24-27-29-30-31-32 |
20 |
794 |
18-24-25-27-28-29-31-32 |
† Numbered increasingly according to the number of bored coffee berries.
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| FIG. A1. Correlation between the observed number of bored coffee berries and the number of bored coffee berries estimated from a sampling (mean of five coffee bushes). The sampling consisted in a counting of the number of bored coffee berries (BCB) in four fruiting branches, located in four stories of each coffee bush, and a counting of the total number of branches (FB). The estimated number of bored coffee berries per coffee bush was deduced: FB × BCB/4. Numbers indicate different groups of five coffee bushes (Table A1). See text for more explanations. |