The Effect of Glasshouse Red Spider Mite (Tetranychus UrticaeKoch) on the Yield of Cucumbers

Resistance in Cucumis sativus L. to Tetranychus urticae Koch. 3. Search for sources of resistance

“…2. The line at 1.9 represents the economic damage threshold as calculated by HUSSEY & PARR (1963). For a well growing crop SCHULZE (1975) found a similar value, but according to his experiences the damage threshold can lie markedly lower in a poorly growing crop.…”

“…The experiment consisted of three replications of four plants per plot, arranged in randomized blocks. Each plant was inoculated with ten adult female mites and the damage caused by the spider mites was scored at weekly intervals on a damage scale designed by HUSSEY & PARR (1963) (Fig. 1).…”

Resistance in Cucumis sativus L. to Tetranychus urticae Koch. 4. The genuineness of the resistance

“…The susceptible control was only inoculated with 20 adult female mites from the basic population. The damage caused by the spider mites was scored at weekly intervals on a damage scale of one to five (1 = slight damage; 5 = heavy damage) designed by HUSSEY & PARR (1963). At each observation date five leaves per plant were judged and the mean value for damage represents the damage index (DE PONTI, 1978).…”

Monitoring of Western Flower Thrips on Glasshouse and Vegetable Crops

“…This threshold is based upon information for spider mites, which cause similar damage on cucumber, where ;;? !30% damage to the leaf surface results in yield loss (Hussey & Parr 1963). However, there are indications that the effect of leaf damage upon yield loss may be reduced if the plant is in a rapid growth phase or has a lot of leaves.…”