and Integrated Pest Management - part - usaid

DEVE.OPMENT OF ACTION CONTROLmTIIREsnotIm FOR MAJOR RJQIPMS 101
Stemborer
ACTs have historically been based on percentage deadhearts.
character
However,
has
this
proven unreliable as the damage is done before an action
taken.
can
Very
be
low control in our trials (14%) supported this observation.
We tried yellow rice borer egg masses as a character (0.5-1 egg masses/m 2 with a sample
)
size of 200 hills. When egg masses were present, we
for
held
parasite
them
emergence before taking action. Spraying is
than
only
50%
done
parasitization
when less
occurs and therefore is timed with larval emergence.
were faced
We
with problems of having whiteheads without egg
overcome
masses.
the
To
problem we set up a light trap to give us warning when
for egg
to sample
mass. We obtained very low control (32%), and feel that pheromone
traps are needed to improve the ACT.
Planthor pers
Our previous ACT for planthoppers was 15 insects (adults and nymphs) per
hill. Because of resurgence due to spraying at the time adults or young nymphs
were present, we improved the ACT by measuring only older nymphs
(0.5/tiller). With this approach, natural enemies were given time to exert their
effect. Sequential sampling, when used together with the ACT, saves valuable
time and is quite effective.
EVALUATION
Threshold technology over sites and seasons for crop year 1985, dry and wet
seasons, were analyzed for economic benefits (Table 3). The untreated resulted in
the highest net benefit (P-7638/ha), followed by farmers' practice (27381/ha),
ACT (P27320/ha), and prophylactic (P-683 1/ha). The benefit-cost ratios from the
farmers' practice and ACT treatments vere almost identical. The ACT
treatments resulted in fewer insecticide applications than the farmers' practice,
but farmers used lower dosages and therefore spent less money. ACTs performed
poorest in sites with highest or lowest yield losses and worked best in sites with
intermediate losses. The ACTs thus need to be adjusted more to site conditions
to bring higher net returns.
LITERATURE CITED
Bandong, J.P. and Litsinger, J.A. 1986. Development and implementation of
rice insect pest management in the Upper Pampanga River Integrated Irrigation
System (UPRIIS) service area, Central Luzon, Philippines. IRRI Saturday
Seminar, 19 April 1986. 21 pp.
IRRI. 1984. Insecticide evaluation for 1983. IRRI, Los Baflos, Philippines.
148 pp.
IRRI. 1985a. Control and management of rice pests. Annual Report for 1985,
pp. 190-216. IRRI, Los Bafios, Philippines.