Introduction

TSA-Biocontrol
Team

Tropical Soda Apple

Insects

Before and After
Gratiana boliviana
Field Release

Publications

Links

Videos

Implementation of Biological Control
of Tropical soda Apple
Gratiana boliviana

The TSA tortoise beetle, Gratiana boliviana Spaeth (Coleoptera: Chrysomelidae) was approved by the USDA-APHIS-PPQ for field release in Florida on May 7, 2003. The initial release of G. boliviana in Florida began in May 14 in Polk County. It was the first biocontrol agent released in Florida for control of Tropical soda Apple. Since the summer of 2003, approximately 232,450 beetles have been released in Florida, Georgia, Alabama, and Texas. This beetle has been established and is dispersing at almost all the release sites.


TAXONOMY AND GENERAL BIOLOGY

Gratiana boliviana lays individual eggs on TSA leaves and petioles. Eggs are initially white in color but turn light green during the incubation period. Each egg is enclosed by two translucent brown membranes. The egg case is attached to the leaf surface by one extreme. A female can produce on average 300 eggs during her 3 to 4 month life cycle. Incubation of the egg takes 5-6 days at a temperature of 25C (77F).

Larvae are cream with a small green spot in the anterior half. Each segment of the body has two lateral processes and a pair of long caudal processes or small forks that arise from the last abdominal segment. Like most tortoise beetles, larvae carry the cast skins on the anal forks with the posterior end of the larva bent forward. The five larval instars can be completed in 15-18 days. Larval feeding is concentrated mostly in the upper third of the plant canopy. Infested plants are easily detected by clusters of small to medium size holes made by the feeding larvae. As feeding progresses, the plants may exhibit large areas of defoliated leaves. Almost complete defoliation has been observed in enclosed cages when the beetle's natural enemies are excluded.

The pupal stage is completed in about 6-7 days. The pupae are green and dorsal-ventrally (from top and bottom) flattened. Pupae are attached to the leaf by the last abdominal segment. The most common pupation place is the underside of leaves. In severely defoliated plants, some pupae can be found on the petioles and stems.

General coloration of the young adult is light green. Along the margin of the elytra (front wings) there is a continous yellow band. The rest of the elytra is light green with irregular yellowish areas between rows or depressions. Mature adults turn a uniform yellow. Females and males can be distinguished by examining the underside of the body. In males, two somewhat rounded orange testes can be observed, one on each side of abdomen. In females there is a pair of white ovaries. Characters for separating the sexes can be observed 3-5 days after emergence. Pre-oviposition (pre-egg laying) period takes from 9 to 12 days. Longevity of females averages 3 months.


Julio Medal   E-mail: medal@ufl.edu
This page was last updated January, 2010