Naslov
The Investigation of the Relationship between WCR Population Level and Corn Yield-Croatian Experiencies

Autori
Dobrinčić, Renata ; Igrc Barčić, Jasminka ; Edwards, Richard C.

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
IWGO Newsletter of the XXI IWGO Conference and VIII Diabrotica Subgroup Meeting / - , 2001, 23-23

Skup
XXI IWGO Conference & VIII Diabrotica Subgroup Meeting

Mjesto i datum
Venecija, Italija; Padova, Italija; Legnaro, Italija, 27.10.2001. - 03.11.2001

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
western corn rootworm; investigation; relationship

Sažetak
It is well known that larvae of Diabrotica virgifera virgifera are oligophagous (Branson and Krysan, 1969, 1970). The only damage effectuated by larvae on cultivated plants was found in corn. Quantitative relationship between population level and corn yield was investigated by Hills and Peters (1971), Trupin et al.(1972), Branson at al. (1980, 1982, 1983), Chiang at al.(1980), etc. Some investigations were caried out under the conditions of artificial infections and in the presence of high natural WCR population levels. Most authors agree that climatic and edaphic factors can impact yield at the same population level. The aim of this study was to check how the USA literature data about the correlation between WCR population level and corn yield corresponds to the Croatian conditions of low to moderate population level. In the region with the higest infestation of WCR, a four year programm started in 1998. in continuous cor fields, emergence cages (3 cages per replicaton) were placed to evaluate number of emerged beetles per plant. To determine the larval populations level in the same fields, 20 plants per replication were dug and root damage (using the Iowa 1-6 scale) was rated. To determine the yield, 20 plants per replication were harvested and the yield was measured. The data from the first 3 years (1998-2000) of the investigation showed that the damage caused by larval feeding on roots in Croatia corresponds to the damage caused in USA. At this level of infestation, the regression coefficient between larval damage and yield could not be established. The literature showed that this coefficient is between 310 and 670 kg/ha of yield loss for each root rating (Iowa 1-6 scale). The full linear correlation (r2=0, 924) between the number of emerged beetles per plant and the root rating was established (y=2.2 + 0.031x). Tirty-two emerged beetles per plant caused an increase in the root damage rating. The data obtained in 2001 will be added to and presented at the meeting.

Izvorni jezik
Engleski

Znanstvena područja
Poljoprivreda (agronomija)

POVEZANOST RADA