Leaffolders

Common name: Black leaffolder

Scientific name: Brachmia convolvuli Wals

Common name: Brown leaffolder

Scientific name: Ochyrotica concursa Wals

Common Name: Green leaffolder

Scientific Name: Herpetogramma hipponalis (Walker)

Leaffolders are considered important defoliators of sweetpotato.

Black and green leaffolders are widespread throughout Asia and Africa and brown leaffolder has only been reported in the Philippines.

Green and black leaffolders

The larvae of these two leaffolders fold the leaf, with the folded area showing some webbing. Then they feed between the folded leaf blade. The young larva feeds on the upper leaf surface leaving the lower epidermis intact. As the larvae mature, they eat through the leaf blade producing lace-like holes with the main veins remaining intact.

Folds are usually single, but sometimes two folds are made, or two leaves are joined together. The holes produced by green leaffolder are generally bigger than those produced by the black leaffolder.

The feeding area may turn brown and is littered with blackish excreta (frass).

Brown leaffolder attacks the shoots and feeds inside the unopened leaves. The young larva feeds on the upper leaf surface leaving the lower epidermis intact.  The damaged tissue may turn brown in response to the injury.  Blackish frass is present and a good indicator that the damage was caused by a caterpillar.  As the larva matures, it eats right through the leaf blade producing irregular holes on the young expanding leaves.

Egg. The eggs are oval, yellowish white when newly laid and turn pinkish yellow when about to hatch.

Larva. Newly hatched larvae are whitish at first turning greenish yellow later without any markings. Markings appear only in the second instar with distinct black and white marks appearing on the head, thorax and first and second abdominal segments. The later instars retain the black markings which become larger and more prominent as the larvae mature. Full-grown larvae measure about 15 mm.

Pupa. The pupae of the black leaffolder are about 7 mm, yellowish brown at first turning dark golden brown later. They have  a tuft of hairs at the tip of the abdomen and are enclosed in scanty cocoon.

Adult. The adults are grayish black moths, 8 mm long, with scattering of white scales on the body and appendages.

Green leaffolder

Egg. The eggs are shiny green, oblong, and covered with a scale-like gelatinous material.

Larva. The larvae are light yellow with dark brown head. A dark brown sclerite appears on the dorsal part of the prothorax in the second instar which becomes divided and appears circular. The body of the later instars turns darker green and the integument appears moist and waxy. Full-grown larvae measure 13 mm.

Pupa. The obtect pupae are yellowish white at first and turn reddish brown. The abdomen tapers anteriorly and has distinct constriction.

Adult. The adults are yellowish brown with dark brown markings on the wings.

The eggs are laid singly along the veins on the underside of the leaf or on the terminal shoots. Incubation period is about 3-5 days. The insect undergoes five larval instars for a period of 2-5 days for each instar. A newly hatched larva is whitish at first. The average total larval period is eleven days. The pupal period is 4-7 days. A female moth lays an average of 44 eggs and lives an average of five days.

Green leaffolder

The female lays an average of 90 eggs per day for three days. The eggs are laid singly or in groups on the upper surface of the leaf, usually near the midrib. Incubation period lasts for 3-6 days. Like the black leaffolder, the first and second instar larvae do not fold the leaf margin. Only the third and later instars fold the leaf margins together using silk threads they spin. The green leaffolder undergoes five larval instars which lasts from 16-31 days. The pupal period lasts from 4-8 days.

The eggs are laid singly along the veins on the shoots, especially on very young unopened leaves. Sometimes eggs are observed on the petiole of the shoots. The female lays 2-10 eggs in seven days. The eggs hatch 4-5 days after oviposition. The insect undergoes five larval instars lasting from 2-4 days per instar. The total larval period ranges from 9-17 days. Pupation lasts for 5-6 days. The duration from egg-laying to adult emergence ranges from 18-27 days. Longevity of adults lasts from 2-7 days.

Beside  sweetpotato, the black leaffolder can complete its development only on two Ipomoea species, Ipomoea triloba and I. aquatica and on a weed, Mikania cordata (Burm. F.) B. L. Robinson (Asteraceae).

Alternate hosts of the brown leaffolder include Ipomea triloba and I. aquatica.

The green leaffolder can only complete its development on Ipomea triloba, I. purpurea, I aquatica, I. pes-caprae and Mikania cordata.

Contributed by: Erlinda Vasquez and Vilma Amante

Taxonomy

Economic importance

Geographical distribution

Damage

Morphology

Biology and ecology

Host Range

Biological control

Management

References

Black leaffolder damage, including folds and scraped patches of leaves (J. O'Sullivan).

Single fold produced by black leaffolder (E. Vasquez).

Fold produced by green leaffolder with web visible through feeding hole (J. O'Sullivan).

Double fold produced by green leaffolder (E. Vasquez).

Browning and holes on young leaves produced by brown leaffolder (E. Vasquez).