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Observers' bias in the assessment of pest and disease symptoms in leek
Author(s) -
Theunissen J.,
Legutowska H.
Publication year - 1992
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1111/j.1570-7458.1992.tb01599.x
Subject(s) - infestation , biology , thrips , pest analysis , crop , rust (programming language) , agronomy , horticulture , toxicology , programming language , computer science
In the vegetable crop leek, Allium porrum L., the performance of observers was compared to the ‘real situation’ of pest and disease infestation. In two experiments the infestation of plants in a number of rows was meticulously investigated thus reflecting the ‘real situation’ as contrasted with the results of one or more observers. Included were the symptoms of leek moth ( Acrolepiopsis assectella Zeller) feeding, both fresh and old, of onion thrips ( Thrips tabaci Lindeman) feeding and of infestation with rust ( Puccinia allii Rud.). The method of scouting was similar to growers' practice in commercial leek growing. The results show that even trained scouts vary considerably in accuracy when assessing infestation in rows at the same field. A group of observers show individual patterns of estimation, a wide variation in ability to make a correct assessment and a strong density dependency of deviations of the ‘real situation’ with the perceived density of the symptoms in the crop.