SPECIES COMPOSITION, ABUNDANCE, AND FORECASTING OF LYGUS BUGS (HETEROPTERA, MIRIDAE) ON FIELD CROPS IN FINLAND

A long-term survey of Lygus populations was carried out on 8 field cro ps in southern Finland. Weekly samples were taken with a sweep net thr oughout the growing season in 16 successive years. The dominant specie s on all crops was L. rugulipennis Poppius, constituting 92% of the to tal number of adults. L. gemellatus (Herrich-Schaeffer), L. pratensis (L.), L. punctatus (Zetterstedt), and L. wagneri Remane occurred in sm all numbers. Bugs were most abundant on wheat. Development of the nymp hs was highly dependent on the temperature in June. The total numbers varied considerably from year to year and were generally highest after warm preceding summers and dry autumns and springs. Multiregressional models were developed to forecast numbers of Lygus bugs.