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Copyright 2005, Board of Trustees, University
WATERMELON INSECT CONTROL
W. C. Adlerz
PESTICIDE LABELS CONTAIN DIRECTIONS FOR SAFE USE AND APPLICATION.
READ PESTICIDE LABELS. FOLLOW DIRECTIONS.
INSECTS SPRAY/ACRE TO HARVEST*
Leaf Cygon 2.67E, 3/4-1 pt. 3
miner Guthion 2E, 1 qt. 1**
Cygon 2.67E, 3/4-1 pt. 3
Melon Parathion 4E, 1/2 pt. 15
aphid P.o3drin 2E, 1 pt. 1
Thiodan 2E, 1 qt. NTL
Lindane 25% WP, 1 lb. 1
Parathion 4E, 1/2 pt. 15
Squash Phosdrin 2E, 1 pt. NTL
bug Sevin 80% WP, 1 1/4 Ibs. NTL
Thioda-i 2E, 2 ats. NTL
Rindworm*** Lannate 90 SP, 1/2-1 b. 3
* "Minimum days to harvest" means the minimum number of days that
should be allowed between last foliar application and harvest.
If recommended dosages are exceeded, the minimum days given may
not be applicable. NTL is the abbreviation for "no time
** Do not apply Guthion to watermelons more than 4 times per
** For large populations or larger worms only the higher rates
may be effective.
*** Biotrol, Dipel, Thuricide. Formulations of Bacillus
thuringiensis. Use the dosage rate indicated on the package.
LEAF MINERS. Leaf miners are most damaging to seedlings and small
plants. They have been known to kill plants in the cotyledon stage,
thereby making it difficult to get plantings established. Plants
in the late running stage seldom need protection. The last severe
outbreak was in southwest Florida in 1961-62.
APHIDS. Aphids may build large, damaging populations on plants of
any size. Aphid outbreaks are sporadic; spray programs should be
initiated as required by conditions. Materials applied for leaf
miner or worm control (other than Bacillus) will also control aphids.
Leesburg ARC Research Report WG74-3
300 copies APR 1 1974
January 22, 1974
RINDWORMS. Worm populations on watermelon have been comprised of
varying populations of up to four species of insects. Worm
populations in central Florida in recent years contained the
Population Cabbage Tobacco Granulate Beet
Year level looper budworm cutworm armyworm
1965 low 33 11 56 0
1966 low 21 34 45 0
1967 low 33 24 43 0
1968 moderate 100 0 0 0
1969 high 100 0 0 0
1970 moderate 100 0 0 0
1971 low 8 51 38 3
1972 very low -
1973 very low I 11 83 5
Eggs are laid on the plants, usually on the under-surface of leaves.
Some cutworm eggs are laid on the ground. Activity usually begins
when plants begin to flower and set fruit. Most worms feed on the
flowers and leaves inflicting little damage. Larger larvae may
feed on the rind surface, defacing the fruit and making it
unattractive for sale. Cutworms most commonly scar the rind near-
the soil surface. When spraying is needed, the control program
should begin shortly after fruit set while worms are still small.
Larger worms are often difficult to control.
WATERMELON MOSAIC. Watermelon mosaic is transmitted by flying
aphids. Most transmission is by aphids that do not colonize
watermelon, therefore extensive infection is possible in fields
where no aphid infestations have been detected. Aphids should
not be allowed to build colonies in mosaic-infected fields, but
aphid control may have no apparent effect in reducing mosaic