Ecological, economic, and environmental assessments of integrated pest management in potato: A case study from the Cañete Valley, Peru

Abstract

Integrated pest management (IPM) versus farmers’ pest management practices were evaluated in potato (Solanum tuberosum L.) in the central coast of Peru. IPM technologies consisted of seed treatment, insect pest, and disease scouting using action thresholds for decision making to apply pesticides, and the use of trapping devices and selective insecticides versus chemical control by potato farmers. An ecological, environmental, and economic analysis of both approaches was carried out by using biodiversity indices, environmental impact indicators, and partial budget analysis. The leafminer fly Liriomyza huidobrensis (Blanchard) and the bud midge Prodiplosis longifila (Gagne) were the most important pests during the cropping season. Larval infestation of both pests and leafminer foliar damage were less in IPM plots. Almost twice as many pesticide (insecticide and fungicide) applications per season were carried out on farmers’ practices plots with 16.7 sprayings compared to 9.7 sprayings in IPM plots. The total quantity of pesticides used per season was higher under farmers’ practices (4,614.3 g a.i./ha) than in IPM (2,042.6 g a.i./ha) plots. Likewise, farmers applied five times more insecticides (3,620.3 g a.i./ha) than IPM (722.55 g a.i./ha). Methamidophos and chlorpyrifos accounted for 65% of the environmental impact (EI) value of 137/ha in farmers’ fields. IPM strategies reduced the EI to 42.4/ha, which represents a reduction of 69.2%. Further, IPM achieved 35% higher marketable potato yield than farmers’ practices. Partial budget analysis showed a higher net profit in all IPM plots, with an average increase of US$1,410/ha. The field trials demonstrated the environmental and economic viability of IPM for potato in the central coast of Peru. However, while there are effective integrated components for leafminer fly management, there is a clear need to develop and integrate more sustainable and ecological pest management strategies for other economically important pests such as the bud midge.

The Potato Crop

“…The AT is typically set below the EIL accounting for the lag time to implement effective control measures. Preemptive insecticidal control is economically not justified until foliar injury exceeds these values Mujica and Kroschel 2018).…”

“…IPM reduced the total quantity of pesticides used per season by 56% compared to the conventional management, representing a decrease of 69.2% in the environmental impact. Further, IPM achieved 35% of higher marketable potato yield than conventional management (Mujica and Kroschel 2018). Leafminer fly is a polyphagous pest and biocontrol-compatible control measures need to be integrated into an IPM concept which considers also other economic pests in potato.…”

“…Therefore, factors that favor vigorous potato plant growth (appropriate fertilization, healthy seed with vigorous sprouts, irrigation, and biostimulants) prevent pest damage by the rapid growth of buds and the exposure of larvae to dehydration and natural enemies. Management practices to reduce infestation include optimal planting density, orientation of the furrows from east to west to favor insolation, elimination of broadleaf weeds, avoidance of susceptible crops, management of the planting season, and rotation with nonsusceptible crops (Mujica and Kroschel 2018).…”

“…Seed treatment with a systemic insecticide protects buds against initial bud midge infestation from emergence to formation of the first leaves and stems. This is a highly recommended practice since it ensures protection for a period of 35 days during a critical period of the crop, without affecting natural enemies (Mujica and Kroschel 2018).…”

“…The International Potato Center (CIP) has developed a holistic working framework for potato pest management research and development and its application by farmers. This approach led, for example, to the development of IPM for different potato agroecologies in Peru under smallholder production considering ecological, economic, and environmental benefits (Mujica and Kroschel 2018;Kroschel et al 2012). Further, Horn and Page (2008) reported from a successful potato IPM program for large-scale potato growers in Australia.…”