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Most
pesticides are applied in liquid form using
backpack sprayers and not all farmers utilize
protective equipment while spraying. Pesticides
also imply a significant economic cost for
producers. Pesticide expenditures typically
comprise between 12 percent and 20 percent of
production costs.
Producers need alternative pest management
approaches that are feasible, economically
sustainable, and effective. Integrated Pest
Management (IPM) can help lower production
costs, reduce exposure to pesticides, and
improve long-term sustainability of the
agricultural system. The national agricultural
research institution in Ecuador (INIAP),
supported in part by the IPM Collaborative
Research Support Program (IPM CRSP) funded by
USAID, has developed technologies to manage
potato pests.
IPM Solutions
Three main pests significantly impact potato
production in Ecuador. They are, in order of
economic significance, late blight (Phytophthora
infestans), the Andean Potato Weevil (Premnotrypes
vorax), and the Central American Tuber Moth (Tecia
solanivora). Studies in the 1990s in northern
Ecuador reported that nearly 100 percent of
farmers were affected by late blight, 80 percent
by Andean Weevil and 6 percent by tuber moth (INIAP,
1998). The IPM CRSP conducted original research
to develop strategies for effective management
of these three pests. Late blight is a fungal
disease that attacks potatoes around the world.
Yield losses depend on the virulence of the
fungal strain and whether farmers have the
resources to use available fungicides. Studies
on lower virulence strains estimate losses at
15-30 percent of the crop (Lang, 2001). Without
chemical intervention, more lethal strains put
farmers at great risk of losing much of their
crop.
The prime means of control for late blight is
fungicide applications. Farmers in Carchi spray
their fields between one and 11 times during a
crop cycle, with most farmers spraying six times
(Barrera et al., 2003; Crissman et al., 1998).
Farmers spray as a preventive strategy because
late blight is difficult to control once the
disease has become established. IPM CRSP
recommendations include: use of resistant
varieties, improved field sanitation,
implementation of crop rotations, monitoring to
determine need for spray applications, and
alternating different types of fungicides to
prevent the buildup of resistance.
The Andean Weevil can also cause significant
damage without proper management. Up to 80
percent crop damage has been estimated in
infested fields in Ecuador. Farmers typically
use three strategies against the Andean Weevil:
insecticides to target the larval stage of the
insect, namely Carbofuran and Methamidofos (both
of which are restricted in the U.S. because of
high toxicity); crop rotations; and use of
undamaged seed.
The IPM CRSP recommends the use of traps to
monitor and target adult populations. Traps
consist of foliage from potato plants baited
with Acefato (relatively low toxicity level). If
populations reach a specific threshold, farmers
are advised to spray at the base of plants since
adult weevils tend to remain at soil level. This
IPM CRSP recommendation is simple to implement
and leads to less costly but more effective
control of the pest. At harvest, the IPM CRSP
recommends that all tubers should be completely
removed from the field. Farmers are advised to
wait 30 days before replanting. The tuber moth
is not yet a big problem for farmers in Ecuador;
however, it has an affinity for temperate
valleys like those found in Carchi. It can cause
damage to pre-harvested tubers as well as stored
potatoes. In either case, current methods of
control use highly toxic insecticides (Carbofuran
and Carbosulfan). In the field, IPM
techniques include: pheromone traps to monitor
and track adult populations and spraying low
doses of Profenos when populations reach a
specified threshold. In storage, farmers are
advised to use baculovirus to kill insects and
keep the harvested potatoes covered. Other
recommendations include: earlier planting and
harvests that avoid the dry season (tuber moths
prefer dry weather to slip between cracks in the
soil), hilling up of soil around plants, crop
rotations, and disinfecting seed with
low-toxicity pesticides such as Carbaryl and
Malathion.
IPM vs. Conventional Technologies: Is IPM
Profitable?
In field trials, cost-benefit analysis was used
to compare conventional to IPM techniques. In
all cases, input costs were significantly lower
on IPM plots. Yields were higher in two out of
three cases, and in the third case, yields were
the same but the costs of production were lower
on the IPM plot. Taking into account costs and
benefits, net profits were higher in all cases
for the field trials, with estimates showing
that the net benefit per hectare of adopting IPM
is between $600 and $800. IPM is a
cost-effective choice for potato farmers and
requires no additional capital. Extra labor only
appears to be necessary at harvest time. Inputs
such as pesticides and fertilizers are used less
in IPM plots and offset the increase in costs
from purchased seeds.
Dissemination of IPM
The IPM CRSP explored alternate means of
technology dissemination because of the absence
of public support for agricultural extension in
Ecuador. Several training and dissemination
methods were used, including training of
trainers, Farmer Field Schools (FFSs), field
days, and written methods. Well over 5,000
farmers in Carchi have been trained through FFSs,
field days, and short workshops. Because of the
relative complexity of the IPM method, studies
have found that a complementary mix of
dissemination methods is most effective, and the
use of these methods has been shown to lead to
widespread adoption of IPM. Estimates show that
more than 50 percent of farmers in the region
are using at least four (out of 17) of the
recommended IPM practices. While FFSs are most
effective at improving the knowledge of
participants about pest management principles,
they are also very expensive and best used in
combination with other less costly methods.
Field School participants are, however, most
likely to share their experiences with others.
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