Seasonal abundance, spatial distribution and sampling indices of thrip populations on cotton; a 4‐year survey from central Greece

Abstract

Field studies were carried out in order to assess the populations of thrips on cotton leaves, by developing a sampling program to estimate the density with an acceptable level of precision. Thus, in a cotton field (1.1 ha) in central Greece, 45 leaves were collected (one leaf per cotton plant) at 10‐day intervals from May to September, for four consecutive growing seasons (1995–98). Five species of thrips were found: Frankliniella intonsa was the most abundant species followed by Thrips angusticeps, Thrips tabaci, Frankliniella occidentalis and Aeolothrips intermedius. Although considerable differences were observed in the population fluctuations among species, the highest population densities, for all species found, were recorded in July and August. As indicated by Taylor's power law estimates, all species presented aggregated distribution among sampling units. As this type of spatial pattern indicates, the accuracy obtained in estimating mean population density increased with the increase of the mean. Furthermore, the increase of the mean caused an exponential decrease in sample size. However, the precision level is acceptable only in high mean values, while at the same time the benefit from an increase in sample size is of no practical value.

Development of a sampling plan for Myzus persicae (Hemiptera: Aphidoidea) and its predator Macrolophus costalis (Hemiptera: Miridae) on tobacco

“…High sample-to-sample variation may also lead to an exponential increase in the sample size required for sufficient precision (Cho et al, 1995;Kapatos et al, 1996;Deligeorgidis et al, 2002). Based on our results, the specific sample size that we used (20 leaves) was rather small to estimate the mean under a very sensitive precision level (D = 10%), especially at low population densities.…”

Distribution of Aeolothrips intermedius Bagnall (Thysanoptera: Aeolothripidae) and its potential prey Thysanoptera species on different cultivated host plants

“…intermedius is the most common species of this genus on the Old Continent (Deligeorgidis et al 2002) and it is frequently mentioned in the context of biological control (von Zegula et al 2003). Adult specimens of this species are quite similar to those of Aeolothrips fasciatus L., so the two species can very easily lead to confusion (zur Strassen, personel communication).…”

The Species Composition and Seasonal Dynamics of Thrips (Thysanoptera) Populations on Maize (Zea Mays L.) in Southeastern Poland

“…Thrips also feed on flowers -interrupting fruit development. Most often, however, thirps do not destroy the plants directly but serve as vectors of tospoviruses, and by sucking plant cells they facilitate the spread of bacterial and fungal diseases (Franssen and Mantel 1965;Lewis 1973;Puche et al 1995;Tommassini and Maini 1995;Deligeorgidis et al 2002).…”