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The European corn borer (ECB), Ostrinia nubilalis (Ht‹ 9 bner) (Lepidoptera: Crambidae), is the major arthropod pest of corn in Croatia. However, chemical control is carried out only in maize for seed production, and in sweet corn. A 3-year investigation was carried out in corn fields in northwest Croatia to establish the most attractive pheromone lure for ECB monitoring, the optimal timing of insecticide applications, and the efficacy of selected insecticides against ECB. During each of the 3 years, the pheromone lures E, Z and E/Z («Isagro») were evaluated in the field from May to July. Insecticides were sprayed 14-20 days after the maximal capture in 2002 and 2003. In 2004, three different trials were set up: one trial with one early treatment (when corn was in the R49 development stage according to the extended BBCH scale); one with one late treatment (when corn was in the R65 development stage according to the BBCH scale); and one with two treatments in both stages. In the trials studying Bacillus thuringiensis var. kurstaki (B.t.k.), insect growth regulators (IGR), spinosad and classical chemical insecticides were applied. Pheromone lure E was the most attractive for monitoring ECB flights throughout 2 years of investigation. Insecticide efficacy depended on application timing. The insecticides most suitable for integrated pest management (IPM) programs, including spinosad, B.t.k. and IGR, resulted in high (spinosad) to moderate (B.t.k.) efficacy. The efficacy of IGRs indicates the need for earlier application. The efficacy of chemical insecticides depended on the year and the insecticide. The organophosphate (OP) insecticides and pyrethroids gave moderate to good results; imidacloprid did not provide significant efficacy. One application of all insecticides based on proper (early) timing resulted in the same efficacy as two applications of the same insecticides.

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Western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, larval damage in maize following soybean was observed in Croatia in 2003 along the edges and within soybean fields which bordered continuous maize fields in previous year. The explanation was that WCR adults moved from the continuous maize to the neighbouring soybean fields to lay eggs. This study was designed to measure how far WCR adults will enter into neighbouring fields to lay eggs. The WCR adult population was monitored in continuous maize fields in 2003 and 2005 by using Pherocon Ò AM non-baited yellow sticky traps in the middle and on the borders of the maize field and at different distances and directions into neighbouring fields planted by wheat and soybean. Larval presence and root damage ratings (Iowa State University 1-6 ) were recorded at different locations within the maize field in following years. Approximately, the same concentration of WCR adults was recorded along the edges of the maize fields as recorded in the centres of those fields. A significant number of WCR adults was recorded up to a distance of 50 m into neighbouring fields. Regression analysis showed medium negative correlation between distance from previous maize field and root damage in the following year. Findings indicate that WCR egg lying can reach approximately 20 m into fields neighbouring maize fields and that significant root damage caused by WCR larvae in first-year maize following soybean and wheat can happen up to a distance of 20 m into those fields. Most farmers's fields in Croatia are up to approximately 50 m wide. As an edge effect for WCR egg laying can reach approximately 20 m into fields neighbouring maize fields, our research results indicate that it is possible to see WCR larval damage in rotated fields without those WCR's being the variant form.

Continuous maize production in Croatia and Central Europe is at serious risk from western corn rootworm (WCR) (Diabrotica virgifera virgifera, LeConte) activity. When alternatives to sowing continuous are not feasible, farmers will need a reliable tool that will allow them to choose fields for continuous cultivation. The decision could be based on assessing the adult populations in fields from the previous year. Non-baited yellow sticky traps [Pherocon AM (PhAM)] could be utilized as a practical tool for sampling. The main objective of this study was to determine which WCR adult population data collected by PhAM traps could most reliably predict the subsequent WCR larval population and damage. Adult WCR population densities in 30 cornfields were determined weekly over a 74 day period each year (24th to 35th week) from 2006 to 2009. In addition to root damage and plant lodging measurements, soil and root sampling were conducted to measure the WCR larval population in continuous maize fields. Larval infestation is best predicted by maximal weekly capture (MWC) but, root damage is better predicted by capture of adults in the 31st week of previous year. For the prediction of plant lodging, MWC, average daily capture (ADC) and the capture of adults in 29th week were found to be equivalent. To save money and to shorten the sampling period, farmers should employ PhAM traps between the 29th and 32nd week. The estimated WCR adult capture that could cause significant larval infestation is ! 22 adults/trap in the 29th week. Significant future root damage is predicted if ! 41 adults/trap are captured in the 31st week. Plant lodging is predicted if ! 36 adults/trap (for 90% of upright plants) or ! 32 adults/trap (for 10% of partially lodged plants) are captured in 29th week. Findings will help to develop economic threshold models and improved decision-making for WCR management.

Several species of the genus Fusarium can cause apple fruit to rot while stored. Since Fusarium taxonomy is very complex and has constantly been revised and updated over the last years, the aim of this study was to identify Fusarium species from rotten apples, based on combined morphological characteristics and molecular data. We identifi ed 32 Fusarium isolates from rotten apple fruit of cultivars Golden Delicious, Jonagold, Idared, and Pink Lady, stored in Ultra Low Oxygen (ULO) conditions. Fusarium rot was detected in 9.4 % to 33.2 % of naturally infected apples, depending on the cultivar. The symptoms were similar in all four cultivars: a soft circular brown necrosis of different extent, with or without visible sporulation. Fusarium species were identifi ed by the morphology of cultures grown on potato-dextrose agar (PDA) and carnation leaf agar (CLA). Twenty one isolates were identifi ed as Fusarium avenaceum and confi rmed as such with polymerase chain reaction (PCR) using specifi c primer pair FA-ITSF and FA-ITSR. F. pseudograminearum, F. semitectum, F. crookwellense, and F. compactum were identifi ed by morphological characteristics. F. avenaceum can produce several mycotoxins and its dominance in Fusarium rot points to the risk of mycotoxin contamination of apple fruit juices and other products for human consumption. Pathogenicity tests showed typical symptoms of Fusarium rot in most of the inoculated wounded apple fruits. In this respect Fusarium avenaceum, as the dominant cause of Fusarium rot in stored apple fruits is a typical wound parasite.