Biology, pattern of infestation and characteristic damage of the citrus rind borer, prays endolemma diakonoff (Lepidoptera: Yponomeutidae) on pummelo, citrus maxima (Burm) merr. (Rutaceae) in Region XI / Leslie L. Toralba ; Virginia R. Ocampo, chair, advisory committee.

Date

4-2011

Abstract

The biology of the Citrus Rind Borer (CRB), Prays endolemma Diakonoff, on pummelo was investigated under field conditions. The egg hatched in 3-4 days. The larval period ranged from 13 to 15 days, while the pupal period last from 4-5 days. Eggs were dome-shaped, almost circular (0.051 ±0.005 mm diam), cloudy white, and laid singly on the fruit surface from fruit set until the fruit measured less than 35 mm diam. The larvae spent the entire five instars inside the rind, particularly in the flavedo, until the fully mature larvae (average length of 5.5 ± 0.22 mm) crawled out from the fruit. The fifth instar larva was distinct from the younger larvae because the former displayed a pattern of red stripes one on each abdominal tergite extending to the lateral margins. The pupa was 4.5 ± 0.5 mm. long and was enclosed in a lacelike, large-meshed cocoon. The adult was generally grayish brown with dark brown markings and measured an average of 4.05 ± 0.605 mm and 4.75 ± 0.69 mm long. The female genitalia showed a distinct ductus bursae with short tubular upper third and sclerotized wide lower part formed of two broad sclerites (cestum), bearing each a dentate ridge from where the species got her name. Twelve days after flower bud formation, 42% of the labeled buds showed damage by CRB and ultimately dropped to the ground while 58% of the buds developed into fruits but were subsequently infested by CRB before they reached the size of less than 35 mm diam. Only 32% of the damaged fruits reached maturity and were harvested. The feeding or larval tunnels were 4-8 mm in length and were confined to the flavedo, just beneath the exocarp. A fruit could support as many as 11 larvae in different stages of development. This could be translated into a series of four egg layings in one fruit developmental period: one from bud formation until fruit set and three during early fruit development. Predation of CRB larvae by a spider (Araneae: Salticidae) and by black ants (Hymenoptera: Formicidae) were observed in the field. No parasites emerged from field-collected CRB.

Document Type

Dissertation

Degree

Doctor of Philosophy in Entomology

College

Graduate School (GS)

Adviser/Committee Chair

Virginia R. Ocampo

Committee Member

Candida B. Adalla, Barbara L. Caoili, Aurora M. Baltazar, Virginia R. Ocampo

Language

English

LC Subject

Citrus Industry -- Philippines, Citrus, Entomology Crop Protection Cluster

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 996 2011 E75 T67

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