WINETECH Technical Yearbook 2020

as eggs during winter, which are laid on the bark of vines and eggs are present throughout the year.

TABLE 1. Quick identification key for distinguishing Plangia graminea from Eurycorypha lesnei adults and nymphs. Characteristic P. graminea E. lesnei

10 15 20 25 30 35 40

Elytra spot (males)

P. graminea E. lesnei

0 5

Adult species abundance

February March

April

May

June

Female ovipositor shape

Month of Sampling

FIGURE 2. Abundance of two adult katydid species in vineyards of the greater Stellenbosch area from February to June 2013. Monitoring Eggs were found to be a good early predictor for katydid abundance later in the season and are therefore recommended as a monitoring tool. The monitoring system of De Villiers and Pringle (2008) was adapted as follows: Five evenly spaced rows FIGURE 1. Abundance of two adult katydid species in vineyards of the greater Stellenbosch area from February to June 2013.

Abdomen (male and female) colouration

PHOTO 2. Katydid nymph and egg inserted into lower tip of vine bark.

Nymphs

WINETECH TECHNICAL YEARBOOK 2020 42