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Sugarcane production
Pests and diseases
Insect pests: Major insect pests are shoot and stem borers,
white fly and stem boring grubs.
a) Shoot and stem borers: These
include the early shoot borer (Chilo infuscatellus), white top
borer (Scirpophaga exceptalis) and stem borer (Sesamia inferens).
They can be controlled by: (1) using a resistant variety, for
example Uthong 3; (2) using chemicals, for example carbofuran
3 % G (30-60 kg/ha) for irrigated conditions, cypermethrin 15%
W/V EC (13 ml/20 l of water) and deltamethrin 3 % W/V EC (10
ml/20 l of water) for rain-fed conditions, and; (3) leaving
waste to cover the field after harvest.
b) White
fly (Aleurololus barodensis): Can be controlled by: (1) an application
of fertilizer at the rate of 300 kg/ha, making the use of chemical
controls unnecessary; (2) weed control, and; (3) in the case
of a severe outbreak, spraying chemicals, such as dimethoate
40 % W/V EC (40 ml/20 l of water) or carbofuran 20 % W/V EC
(50 ml/20 l of water).
c) Stem-boring grub (Dorysthenas
bugueti): Can be controlled by: (1) hand picking one or two
times before planting; (2) crop rotation with cassava or pineapple,
and; (3) an application of endosulfan + BPMC 4.5% G (30 kg/ha)
in the furrows during planting.
Diseases:
a) White
leaf disease (phytoplasma): The disease can be distinguished
by a chlorosis of the leaves. It can be controlled by: (1) roguing
of the diseased canes; (2) using disease-free cane setts that
have been treated with hot water at 50oC for 2 h or dipped in
tetracycline HCl (500 ppm) for 30 minutes before planting, and;
(3) using tolerant cane varieties, for example, K 88-102.
b) Green
grassy shoot disease (GGSD-phytoplasma): It is typically recognized
by profuse tillering with narrow green or pale green leaves.
It can be controlled by: (1) roguing of the diseased canes,
(2) using cane setts which have been treated with hot water
at 50oC for 2 hr, and (3) using tolerant cane varieties for
example Uthong 3.
c) Smut (Ustilago scitaminea):
The symptom is easily recognized by the obvious whip-like sorus
that arises from either the terminal meristem or lateral shoots
of the infected stalk. It can be controlled by: (1) using the
resistant varieties Uthong 1, Uthong 2, Uthong 3 and Uthong
4; (2) using disease-free planting materials; (3) roguing of
the diseased shoots or stools, and; (4) in the case of disease-free
multiplication plots, cane setts should be dipped in fungicides,
for example propiconazol 10 % W/V EC (40 ml/20 l of water) or
triadimefon 25 % WP (50g/20 l of water) for 30 minutes before
planting.
d) Red rot wilt (Colletotrichum
falcatum and Fusarium moniliforme): In the early growth stage,
plants become yellow. After 5-6 months the stools die. The internal
symptoms initially begin with a red rotting tissue, which can
at times turn gray. The stem becomes hollow and dry with the
cavity being occupied with the fungus mycelia and sometimes
with fruiting bodies. The yield loss is up to 40-50 percent
in plant cane and 100 percent in ratoon cane. The disease can
be more serious in lowland plantations with poor drainage. It
can be controlled by: (1) using the resistant varieties K 84-200,
K 88-92, K 90-54, K 90-77 and Uthong 3; (2) roguing of the infected
cane; (3) incorporating a crop rotation; (4) sun drying the
soil for 3 months; (5) using disease-free cane setts, and; (6)
using a fungicide such as benomyl 50 % WP (15g/20 l of water)
or thiabendazol 90 % WP (15g/20 l of water) in which the planting
setts are soaked.
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