Leaf hoppers are sap-sucking pests that feed on plant leaves, twigs, stems and generally any vegetative part of a crop. They are also known as tree hoppers or plant hoppers owing to their modified hind legs which they use to hop whenever disturbed.
They are mostly named based on host plant/ family attacked, e.g. beet leaf hopper, rice green leaf hoppers, maize green leaf hoppers, grape leaf hoppers, variegated leaf hoppers etc.
These leaf hoppers are both pests and vectors of various plant viruses and phytoplasm.
LIFE CYCLE
Leaf hoppers undergo incomplete metamorphosis as they hatch from eggs and mature through multiple nymphal stages before reaching adulthood.
Females lay their eggs on the veins of the underside leaf or any tender plant tissue. On average 100 eggs are laid and this depends on temperature.
Eggs inserted in the tissue form “pimple-like” injuries that are more noticeable than the insects themselves. Hatching occurs in 6-9 days and begins once temperatures are high enough, whereby wingless nymphs emerge. These nymphs undergo five instars before maturing.
Nymphs at the late instars resemble the adult with the only difference being lack of wings. In 2-7 weeks’ time, adults emerge and start feeding by piercing into plant parts and sucking the sap.
Leaf hoppers overwinter as eggs on twigs or as adults under the barks of the host plant.
The period from egg to adult is about three weeks. Several overlapping generations may be completed during the growing season.
DESCRIPTION
Adults
They are slender, wedge-shaped and 1/4 inch long. They have varying body colors of green, yellow, brown and are often mottled.
Most species are brightly colored while others match the color of the host plant.
They have red-tipped antennae and two tube-like structures protruding from the hind end.
Some species have small brown or black spots between the eyes on the front margin of head’s crown while others have two small black spots and brown marks behind the eyes extending along the body.
Eggs
They are elliptical and narrow and approximately 0.3-0.5 mm long by 0.1 mm width wise.
Nymphs
They look like smaller adult leafhoppers, but they do not have wings and therefore, jump about if bothered.
Early instar nymphs are pale green – yellow while the late instar nymphs resemble the adults and have a dark coloration.
DAMAGE
Leaf hoppers are sap sucking pests and cause several damages on the host crop.
Their damage is characterized by light-colored speckling on plant leaves caused by their sucking sap and plant juices from within the plant tissue. When left unchecked, this gradual feeding reduces the plant’s vigor over time, browning the leaves.
Damage caused by leafhoppers is usually not severe enough to seriously harm mature plants, however, young plants or new growth can be stunted and/or deformed by leafhopper feeding.
Their toxic saliva causes leaves to appear stippled, pale or brown. Infested shoots curl and die while the tips of infested leaves develop diamond- shape yellowing.
Leaf hoppers transmit organisms that cause viral diseases and phytoplasmas.
For instance, Maize leaf hoppers which transmit maize streak monogeminivirus (MSV) disease which causes yellow streaks, plant death, dieback or dwarfing.
Some species secrete honey dew on foliage which favor the growth of sooty mold. As such, photosynthetic area is reduced.
MANAGEMENT
Chemical method
The following insecticides are fit for use against leaf hoppers.
- PRESENTO 200SP 5g/20l
- KINGCODE ELITE 50EC 10ml/20l
- SINOPHATE 750SP 20g/20l
- LEXUS 247SC 8ml/20l
- AMAZING TOP 100WDG 5g/20l
- DEFENDER 25EC 40ml/20l
- EMERALD GOLD 700WP 5g/20l
- PROFILE 440EC 30ml/20l
- LEGACY 50EC 15ml/20l
- EMERALD 200SL 10ml/20l
- LOYALTY 700WDG 5g/20l
Non-chemical methods
- Avoid/reduce overwintering sites by removing all garden trash and other debris after harvesting.
- Planting crops away from favored hosts.
- Planting companion crops such as marigold and geraniums.
- Use floating row covers as a physical barrier to keep leafhoppers from damaging plants.
- Use commercially available beneficial insects, such as ladybugs, lacewing and minute pirate bugs, which are voracious predators of both the egg and young larval stage.
- Plant resistant cultivars
- Practise rotations with non-host crops
Tips!
- Always mix the insecticide with INTEGRA 3ml/20l, which is a sticker, wetter, spreader and penetrant that improves efficacy of the chemical.
- A single spray is never adequate. Always do repeat sprays for effective control.
- Timely management of the pest is very important.
