Cultural Practices

Cucurbits grown in Illinois include cucumbers, cantelopes, watermelons, squash, and pumpkins. These cucurbits are warm weather plants. Their growth, yield and quality is best on warm, sunny days. these cucurbits are subject to attack by a number of insect pests, each of which has a recommended
chemical control. Although these pests are capable of causing extensive damage, they can be managed effectively with scouting and well-timed control procedures.

Specifics for cucumbers:
Cucumbers grow best in sandy soil and warm weather. However, they do need 1-2 inches of water every week, with more needed in hot or dry weather. Plastic mulch and drip irrigation can improve yields and earliness. Good drainage is also important in the production of good fruit. Raised 18-inch wide beds on 48-inch centers are often used to provide a level planting surface and good drainage. The height of the bed depends on how well the soil drains. Planting depth is 1/2 to 1 inches. Rows are usually 38-48 inches apart with 6-8 inches between plants.Soil temperatures should be at least 60° F to ensure proper growth. The higher the soil temperature, the more rapidly seedlings emerge and the less vulnerable they are to seed corn maggots and damping-off diseases. Seeds should always be planted late enough to avoid frosts. Cold temperatures
will slow the growth. Optimum temperature is 65-75° F.

For earlier cucumber production and higher, more concentrated yields, use gynoecious varieties. A
gynoecious plant produces only female flowers, thus producing the fruit.

Honeybees are important for pollination, high fruit yields and quality. Populations of pollinating
insects may be adversely affected by insecticides applied to flowers or weeds in bloom. Use one hive
per acre to get good pollination. Apply insecticides only in the evening hours or wait until blooms
have closed before application.

Specifics for watermelons:

All seedless watermelons should be transplanted since high percentage germination of seed requires a specific environment. Since seedless watermelons produce inadequate pollen, a seeded variety must be planted every third or fourth row to ensure good pollination of seedless watermelons. The seeded variety should also be marketable and easily differentiated from the seedless variety so that no mixing of varieties occurs at harvest.The recommended spacing for watermelons is 5 to 6 feet between rows with 3 to 4 feet between plants in the row. Moist, sandy soils are best suited to sustain a watermelon crop.Honeybees are important for pollination, high fruit yields and quality. Populations of pollinating insects may be adversely affected by insecticides applied to flowers or weeds in bloom. Use one hive per acre to get good pollination. Apply insecticides only in the evening hours or wait until blooms have closed before application.

Insects
Aphids (Aphis gossypii)

Aphids are 1/16 inch long insects that can be seen in many different colors. They colonize on the
underside of leaves and have a 5-7 day reproduction cycle.
Damage: Aphids feed by sucking the sap from plant leaves and also leaving behind honeydew secretion.
Sucking the sap from the plant causes leaves to curl up and die. Furthermore aphids can transfer
mosaic viruses during feeding. The virus causes leaf deformity as well as a light and dark green
mottled look.

Control: Insecticides are not effective for control, but keep in mind that late planting contributes
a heavy infestation.
Cabbage Looper (Trichoplusia ni) 2
The Cabbage Looper is a 1 to 1 and 1/2 inches long green measuring worm with thin white stripes down its back and sides. They overwinter as pupae. In the spring, cabbage looper moths emerge form their cocoons. After mating, eggs are laid on upper leaf surfaces of brassica plants. Larvae hatch several days later and feed for about a month on leaves. After many instars, mature larvae spin a cocoon and pupate. Several generations can occur in one year because the time from hatching to adult takes under a month.

Cucumber Beetles, Spotted and Striped (Diabrotica undecimpunctata and Acalymma vittatum)

The striped cucumber beetle overwinters as an adult and appears in the early spring. These beetles
are characterized by black stripes down the length of their back and a black abdomen. They lay eggs
in the soil near host plants. The striped cucumber beetle should not be confused with the western
corn rootworm beetle- this insect does little damage and is differentiated by its yellow abdomen.
The spotted cucumber beetle (a.k.a. the southern corn rootworm beetle), is greenish-yellow with 12
black spots on its wing covers. They emerge in mid summer (late June to early July) and feed on
cucurbit plants. This feeding can be extremely dangerous for young plants; often leading to stunted
growth or death.

Damage: Beetles feed on cotyledons, plant stems, foliage, blossoms and true leaves of cucurbits.
Striped cucumber beetle larva feed on roots and inside underground stems, which often results in
severe damage to underground root systems. These beetles, when feeding, are also able to transmit
bacteria, which can potentially cause bacterial wilt. The bacteria clog water conduction tubes
within the plant and lead to permanent wilt. Evidence of this infestation will take 2 – 6 weeks to
emerge; nothing can be done once a plant has been infected. Thus the only prevention for bacterial
wilt is the elimination of cucumber beetles.

Control: Scouting field edges is mandatory for control of beetles. They will start in on edges and
move into the field 24-36 hours later. They will start to mass quickly- this action calls for weekly
sprays until the problem is eliminated. After elimination, scouting should continue in a 'Z'
formation across fields. In the 'Z' formation, five stops should be made, counting ten plants at
each stop. If beetles reappear, a minimum of one per plant must exist before insecticides can be
administered. Most growers apply a systemic insecticide- Furadan- which gives 2-4 weeks of control.
But if beetles emerge in late, soil treatment may not be enough; foliar insecticides will have to be
used. Foliar varieties with a 5 –7 day residual is most effective. In times of severe infestations,
applications may be necessary every five days (high means >20 insects per plant).
Greenhouse Whitefly (Bemisia spp.)
Whiteflies are 1/16 inch long insects with four pairs of rounded white wings and a yellow body. They
colonize the underside of leaves. Feeding is accomplished by piercing the leaf and sucking the sap
out of the leaves. Whiteflies have a 21-36 day life cycle, yielding 8-10 generations per year.
Damage: The leaf feeding causes leaves to become speckled yellow or silvery.
Control: Natural predators such as Encarsia formosa help control whiteflies. If necessary, chemicals
such as malathion, thiodan, orthene, talstar, tempo, sumithrin, mavrik or marathon maybe used.