Cocoa Pod Borer (Conopomorpha cramerella Snellen) in Papua New Guinea: Biosecurity Models for New Ireland and the Autonomous Region of Bougainville

Abstract

Cocoa Pod Borer (Conopomorpha cramerella Snellen) (CPB) is an important pest of cocoa. Following its emergence as a pest in East New Britain, Papua New Guinea, in 2006, it was considered relevant to assess its potential spread to other cocoa growing regions. Its likelihood of introduction to the islands of Bougainville and New Ireland from East New Britain Province, Papua New Guinea, was modeled using Monte Carlo simulation. This dispersal model was based around different scenarios, identifying trends rather than explicitly attempting to encapsulate true values. The model suggested that CPB is far more likely to establish on New Ireland than on Bougainville. More important, incertitude resulting from incomplete knowledge of the amount and frequency of cocoa transported between islands had a significant effect on model outputs. Quarantine and agriculture officials will be able to refine these parameter values, and then use the relevant scenarios from those presented here as a guide to develop quarantine procedures. In addition, a contingency model was employed to estimate the optimal sampling effort to use following an incursion of CPB into Bougainville or New Ireland and the seemingly successful implementation of an initial eradication program. The model suggests that at a 1% infestation level, sampling should continue for 2.5-2.7 years (90% CI) after claiming eradication, and this estimate changed little for higher infestation levels. Through modeling variations in sampling intensity, the model also suggested that determining the full spread of CPB is more important than increased sampling within one region.

Enriched cocoa pod composts and their fertilizing effects on hybrid cocoa seedlings

“…Proper waste recycling strategy has become all the more important with the outbreak of cocoa pod borer (Conopomorpha cramerella Snellen; family: Gracillariidae) (Yen et al 2010). The cocoa pod borer (CPB) larva causes damage to cocoa by boring into the pod and disrupting the development of the beans.…”

“…Hence, of cocoa growers abandon CPB-infested pods and opened husks in piles scattered on the farms thus directly contributing to the multiplication of CPB. The husks and pods scattered on the farm, can also harbor and pre-dispose spread of black pod disease (Phytophthora palmivora) inoculum (Yen et al 2010).…”

Uncertainty and sensitivity analysis in quantitative pest risk assessments; practical rules for risk assessors

“…The uniform distribution, which gives equal weight to each value within the uncertainty range, is commonly used when the main objective is to understand model behaviour, but more flexible probability distributions are sometimes needed to represent the input and parameter uncertainty. When the model input corresponds to a discrete variable, for example, the number of imported consignments, or number of successful incursions, discrete probability distributions such as the Poisson are often appropriate (e.g., Yen et al 2010). Among continuous distributions, the well-known Gaussian distribution is often convenient, since it requires only the specification of a mean value and a standard deviation.…”

“…Among continuous distributions, the well-known Gaussian distribution is often convenient, since it requires only the specification of a mean value and a standard deviation. It is often replaced by the truncated Gaussian distribution, triangular, or by beta distributions, which give upper and lower bounds to the possible values (e.g., Peterson et al 2009;Yen et al 2010). When the distribution should be asymmetric, for example, when input factors are likely to be near zero, log-normal, triangular, or beta distributions offer a large range of possibilities (e.g., Peterson et al 2009).…”

Safe handling and movement of cocoa germplasm for breeding

“…Since there was little genetic resistance amongst cultivated varieties, the introduction of the disease had a devastating impact on yields and consequently the economy and employment within the region (Pereira et al, 1996). Other examples of disease and pest movement include the spread of frosty pod rot within Central America (Phillips-Mora et al, 2006) and the spread of the cocoa pod borer within South East Asia (Yen et al, 2010). These examples serve to illustrate the dangers of new pest and disease encounters in a region or country and hence the vital need for quarantine measures.…”