THE OCCURRENCE AND HARMFULNESS OF Oscinella frit L. (DIPTERA: CHLOROPIDAE) TO MAIZE CULTIVARS CULTIVATED FOR GRAIN IN SOUTH-EASTERN POLAND

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1 ISSN ISSN (online) Acta Sci. Pol. Agricultura, 14(3) 2015, THE OCCURRENCE AND HARMFULNESS OF Oscinella frit L. (DIPTERA: CHLOROPIDAE) TO MAIZE CULTIVARS CULTIVATED FOR GRAIN IN SOUTH-EASTERN POLAND Paweł K. Bereś Institute of Plant Protection National Research Institute in Poznań 1 Abstract. Long-term studies on the occurrence of frit fly (Oscinella frit) on maize were carried out in , in Krzeczowice, south-eastern Poland. In the analysed period, O. frit larvae damaged from 3.5 to 42.2% of plants of a medium-early maturing (FAO 240) maize cultivar (mean 25.2%), causing theoretical loss in grain yield from 0.4 to 8.1% (mean 4.5%). Studies on the susceptibility of maize to frit fly were carried out in on 18 cultivars from three earliness categories: early (FAO ), medium-early (FAO ) and medium-late (FAO ). In the analysed 3-year period larvae of O. frit damaged, on average, from 20.4 to 32.3% of plants of cultivars, causing a mean theoretical loss in grain yield from 2.9 to 4.7%. Statistically significant differences were found between the susceptibility of cultivars to damage caused by O. frit. Medium-late maturing maize cultivars were significantly more often damaged by frit fly than the early maturing cultivars. Key words: cultivars, frit fly, maturity class, Poland, susceptibility, Zea mays INTRODUCTION Maize (Zea mays L.) has recently become one of the major crops grown in Poland. The acreage of this plant increases yearly, and in it reached a level of m ha [GUS 2013, 2014]. The increasing acreage of maize and its dominant position in the crop rotation system on farms have resulted in a greater threat to this plant posed by harmful organisms, of which pests play a more and more significant role [Bereś and Pruszyński 2008]. Corresponding author: dr hab inż. Paweł K. Bereś, prof. nadzw. IOR-PIB, Institute of Plant Protection National Research Institute in Poznań, Regional Experimental Station in Rzeszów, Langiewicza 28, Rzeszów, beresp@iorpib.poznan.pl Copyright by Wydawnictwa Uczelniane Uniwersytetu Technologiczno-Przyrodniczego w Bydgoszczy, Bydgoszcz 2015

2 16 P.K. Bereś Currently in Poland maize fields are threatened by over 50 pest species, most of which belong to the Insecta class [Bereś 2013]. Frit fly (Oscinella frit L.) is one of the major pests emerging during spring [Lisowicz 2001, Mrówczyński 2013]. Apart from Poland, this insect has also been reported in other European countries, e.g. Hungary, France, Spain, Italy, Denmark and Germany [Meissle et al. 2010]. The first information on damage to maize plants in Poland caused by O. frit dates back to the 1950s and concerns the Wrocław region, where at that time the whole national maize acreage was located [Kania 1962]. The harmfulness of frit fly to maize increased as the cultivation of this plant became more popular. Lisowicz [1994] indicated the key factors responsible for the increase in the occurrence and harmfulness of O. frit to maize in Poland, such as decline in the acreage of oats, which as alternative host used to create conditions favourable to the development of this pest; earlier sowing of spring cereals, which made these crop species less frequently infested by the spring generation of frit fly; local increase in the acreage of grasses for seed production, which are a overwintering habitats for this pest, and the synchronised dates of the mass flight of adult O. frit individuals from overwintering places with the emergence of the first leaves of young maize plants, being attractive for oviposition. Under the soil and climatic conditions of Poland frit fly produces three generations per year, and the most harmful to maize are the first generation larvae emerging from April or May and usually feeding up to the end of June [Bereś 2014]. Lisowicz and Tekiela [2004] reported that the mean loss in maize yield caused by the feeding of O. frit accounts for about 10%. In addition, this pest increases the susceptibility of maize plants to pathogens, particularly fungi such as Ustilago maydis (D.C.) Corda. As early as the 1970s researchers pointed out that the larvae of frit fly are economically significant and may cause loss in grain yield from 360 to 960 kg ha -1 [Dolinka and Zscheischler 1970]. Since the enforcement of integrated plant protection in the European Union from 2014 the population and harmfulness of weeds, diseases and pests should at first be controlled by non-chemical methods and, if these are ineffective, the use of chemical methods is allowed. One of the nonchemical methods is the cultural one, involving the sowing of cultivars less susceptible to damage caused by harmful species [Matyjaszczyk 2013, 2014]. The aim of this study was to identify the degree of infestation and estimate the harmfulness of frit fly on maize grown in Krzeczowice in This study is the next stage of research initiated in 1997 by Lisowicz [2001] and carried out up to the year In addition, we analysed the susceptibility of 18 selected maize cultivars from different earliness categories (FAO from 190 to 280) to damage caused by frit fly. MATERIAL AND METHODS The study was carried out in Krzeczowice, south-eastern Poland (49 59' N; 22 27' E). The occurrence and harmfulness of frit fly larvae was monitored in on the Limko medium-early maize cultivar (FAO 240), and in on the San mediumearly cultivar (FAO 240). In an experiment was established to assess the susceptibility of selected maize cultivars of different earliness to the larvae of O. frit. In the experiment we used 18 maize cultivars, representing 3 categories of earliness identified in Poland: Acta Sci. Pol.

3 The occurrence and harmfulness early (FAO ): KB1903, ES Ballade, Cedro and NK Ravello, medium-early (FAO ): Dumka, Lober, DKC 2960, Eurostar, Nekta, Zidane and KWS 5133 ECO, medium-late (FAO ): DKC 3420, Ronaldinio, Vitras, Koherens, KB2704, Chambord and Krabas. Long-term monitoring of the occurrence and harmfulness of frit fly larvae and studies on the susceptibility of selected maize cultivars to damage caused by this pest were carried out on 50 m 2 plots (4 rows of 16.5 meter length) using the random block method in four replications. In all years maize was grown in a crop rotation system. No insecticides were used for the control of frit fly and other pests on experimental plots. Maize was sown at an optimum date for this part of the country, i.e. in the last ten days of April. The harmfulness of O. frit larvae was assessed in the second half of June, when maize plants were developing 8-9 leaves (BBCH 18-19) [Adamczewski and Matysiak 2011]. For that purpose on each plot plants in two central rows (50 consecutive plants in each row, 100 plants per plot in total) were inspected by searching for symptoms of larval feeding on above-ground plant parts. Based on this, the mean percentage of plants damaged by the pest was calculated. To determine the degree of damage in individual maize cultivars caused by frit fly we used a 4-degree scale proposed by Lisowicz [1996], where individual degrees indicate: 1 o minor damage to leaves (minor discolourations along leaf veins resulting from larva feeding), 2 o moderate damage to leaves (numerous discolourations along leaf veins, sometimes with small perforations; newly formed leaves unfold with difficulty), 3 o severe damage to leaves (newly formed leaves unfold with difficulty; leaves are curly and lacerated, with numerous cracks along leaf veins), 4 o severe plant damage (growth cone destroyed, main stem decayed, side shoots produced or plant death). Theoretical loss in grain yield was calculated using the formula below: (n1 8) + (n2 25) + (n3 60) + (n4 90) Sp(%) = n where: Sp loss in grain yield expressed in %, n1, n2, n3, n4 number of plants with a damage degree 1, 2, 3, 4, n total number of analysed plants. Results for the susceptibility of maize cultivars to frit fly were analysed using statistical methods. The analysis of results from 3 years was based on a mixed variance analysis design which assumed a constant effect for a cultivar and a random effect for a study year. The significance of differences between mean values was analysed using the Tukey test, at a significance level of p < Regression analysis was used to estimate cause-and-effect relationships between the earliness of the studied cultivars expressed Agricultura 14(3) 2015

4 18 P.K. Bereś by the FAO number and the percentage of damaged plants and the theoretical loss in grain yield. Mean values from 3 study years (N = 54) were used for the formulation of regression equations. All calculations were carried out in Statistica 10.0 PL software. RESULTS AND DISCUSSION In weather conditions in Krzeczowice varied significantly. In the weather between April and May was unfavourable for the intense flight of adults and eggs laying. In these years a prolonged drought was observed (2002, 2004), but also low temperatures and heavy rainfall (2001, 2003) at an early period of maize vegetation, which did not favour infestation by adult individuals, oviposition and larvae development. The weather improved in these years usually in late May or in June, so maize plants grew rapidly. In the weather was more favourable for the development of frit fly. In April and May low temperatures were recorded frequently, delaying the growth of maize plants but also facilitating the infestation of plants by O. frit. Temperatures usually increased from June, contributing to the rapid growth of plants. The monitoring of the occurrence and harmfulness of frit fly carried out in Krzeczowice in demonstrated variable harmfulness of the pest s larvae. During the study period larvae of O. frit damaged from 3.5 (2001) to 42.2% plants (2014) of Limko and San maize cultivars, and on average 25.2% of plants in the analysed 14-year period. Low harmfulness of frit fly was found in , when its larvae damaged from 3.5 to 13.5% of maize plants. Increased harmfulness of the pest was observed from 2007, and at that time in Krzeczowice larvae damaged over 30% of plants each year (Fig. 1). The analysis, focused on the degree of damage to maize plants caused by larvae of O. frit, demonstrated that in the theoretical loss in grain yield was from 0.4 (2003) to 8.1% (2007), with a 4.5% mean loss in the 14-year period. The lowest loss in yield (below 1%) was recorded in 2001 and 2003, and the highest (over 6%) in 2007 and (Fig. 1). The theoretical loss in maize grain yield depended on the degree of damage to plants by larvae, assessed by using the 4-degree scale proposed by Lisowicz [1996]. In all study years minor and moderate damage to maize leaves (degrees 1 and 2) were observed most frequently. An increase in the number of plants with severe damage caused by O. frit (degree 3 and 4) was recorded in 2007 and , and this was probably associated with weather conditions limiting the intense development of maize plants. Slower growth of maize may be a factor increasing the harmfulness of frit fly, because larvae may cause more severe damage to leaf buds and the growth cone. Lisowicz [1979] also reported that intensely growing maize plants are able to spontaneously expel larvae outside the tissues, which is usually followed by larvae death in the environment. A comparison of results from our study with observations made by Lisowicz [2001] in Krzeczowice in revealed that the occurrence of frit fly varied significantly also in the earlier years. Lisowicz [2001] reported that in the analysed long-term period the lowest harmfulness of larvae (1-2% of damaged plants) was found in 1993 and , while in 1981, 1983, 1988 and 1990 larvae of O. frit damaged each year about 70% of plants. In our study no such great harmfulness of this species was Acta Sci. Pol.

5 The occurrence and harmfulness recorded. According to Lisowicz [2001] the harmfulness of frit fly decreased significantly in , and this situation continued in the study region up to the early 2000s, as confirmed in our research. However, the increase in the harmfulness of the pest from 2007 was half lower than that observed by Lisowicz [2001] in the previous century. In our study we also found significantly lower theoretical loss in maize grain yield (on average 4.5% in ) than that calculated by Lisowicz [2001] for previous years. Lisowicz reported that in the mean loss in maize grain yield caused by feeding larvae of O. frit was 9.5%, with the highest loss in grain yield (15 to 33%) observed in , 1998, 1990, 1992 and From the end of the 1990s the loss in grain yield caused by feeding larvae did not exceed 2% [Lisowicz 2001]. Fig. 1. Harmfulness of Oscinella frit to maize in Krzeczowice in Rys. 1. Szkodliwość Oscinella frit dla kukurydzy w Krzeczowicach w latach Results from the analysis of the susceptibility of 18 selected maize cultivars from different earliness categories to damage caused by O. frit are presented in Table 1 and Table 2. The harmfulness of frit fly in varied and was largely influenced by weather conditions. On average 27.7% of plants of all 18 analysed cultivars were damaged in the 3-year period, while the mean theoretical loss in grain yield was 4.0%. In 2009 larvae of O. frit damaged on average 28.8% of plants from all analysed cultivars, causing a mean theoretical loss in grain yield of 3.0%. The lowest number of damaged plants was found for the early maturing Cedro cultivar (19.0%), and the highest on the medium-late Vitras cultivar (38.5%). The lowest loss in yield resulting from the degree of damage to plants caused by larvae was found for the Cedro cultivar (1.7%), and the highest for the medium-early Lober cultivar (4.2%). In the analysed year we found statistically significant differences between the investigated cultivars in terms of the percentage of damaged plants. Plants of early cultivars were damaged least when compared to cultivars from the two other categories of earliness (Tables 1, 2). In 2010 frit fly damaged on average 25.3% of plants from the analysed cultivars, causing a mean 3.4% theoretical loss in grain yield. In 2010 the lowest number of damaged plants was found for the early maturing KB1903 cultivar (18.0%), and the highest on the medium-late Vitras cultivar (31.3%). However, no statistically significant Agricultura 14(3) 2015

6 20 P.K. Bereś differences were found between the analysed cultivars in terms of the percentage of damaged plants. The lowest loss in grain yield was found for the Cedro cultivar (2.4%), and the highest for the Chambord cultivar (4.2%) (Tables 1, 2). Table 1. The percentage of damaged plants by Oscinella frit in Krzeczowice in Tabela 1. Procent roślin uszkodzonych przez Oscinella frit w Krzeczowicach w latach Damaged plants in the years Rośliny uszkodzone w latach, % Cultivar FAO number Odmiana Liczba FAO mean średnia KB de 18.0 a 26.5 ab 21.4 ef ES Ballade de 19.5 a 23.8 ab 21.6 def Cedro e 19.8 a 22.5 b 20.4 f NK Ravello de 19.5 a 25.8 ab 22.2 c-f Dumka a-e 22.8 a 25.5 ab 25.2 b-f Lober ab 25.5 a 25.8 ab 29.5 a-e DKC cde 30.0 a 30.5 ab 28.2 a-f Eurostar b-e 26.3 a 27.8 ab 26.9 a-f Nekta abc 25.5 a 33.5 ab 30.9 ab Zidane a-e 22.8 a 28.3 ab 27.1 a-f KWS 5133 ECO a-e 29.3 a 28.0 ab 28.6 a-f DKC a-d 26.5 a 31.8 ab 29.7 a-d Ronaldinio a-e 25.0 a 28.8 ab 27.0 a-f Vitras a 31.3 a 34.3 ab 34.7 a Koherens a-e 30.5 a 36.3 a 32.3 ab KB ab 27.8 a 30.3 ab 31.8 ab Chambord abc 29.5 a 33.5 ab 32.2 ab Krabas a-e 27.5 a 31.5 ab 29.8 abc Mean for Średnio za lata means followed by the same letter do not differ at 5% level of significance (Tukey s multiple range test) średnie oznaczone tą samą literą nie różnią się na poziomie istotności 5% (test wielokrotnych porównań Tukeya) In 2011 the harmfulness of frit fly larvae increased slightly, and they damaged on average 29.1% of plants from the analysed cultivars, causing a mean 5.5% theoretical loss in grain yield. Similar to the year 2009, the least damage was found on the Cedro cultivar (22.5%). The highest number of damaged plants was found for the Koherens cultivar (36.3%). The lowest loss in grain yield was found for the Cedro cultivar (3.7%), and the highest for the DKC2960 and Vitras cultivars (6.7%) (Tables 1, 2). Two regression equations were formulated after the analysis of cause-and-effect relationships between the studied parameters. The first equation (Y1) describes the effect of cultivar earliness on the percentage of damaged plants, and the second equation (Y2) describes the effect of cultivar earliness on the theoretical loss in grain yield. The regression analysis demonstrated a significant effect of maize cultivar earliness on the degree of damage caused by frit fly. As indicated by the formulated regression equation Y1 an increase in FAO number by 10 units resulted in increased damage to plants by 1.28%. The earliness of cultivars expressed in FAO number determined the degree of damage to maize by frit fly in 54%, while the theoretical index of yield loss only in 11%: Y1 = (FAO) 3.28 for R 2 = 0.54; N = 54; p < Y2 = (FAO) 0.27 for R 2 = 0.11; N = 54; p < Acta Sci. Pol.

7 The occurrence and harmfulness Table 2. Theoretical yield losses in maize grain in Krzeczowice in Tabela 2. Teoretyczne straty w plonach ziarna kukurydzy w Krzeczowicach w latach Cultivar FAO number Theoretical grain yield losses in the years Teoretyczna strata w plonie ziarna w latach, % Odmiana Liczba FAO mean średnia KB ef 2.7 ab 5.0 b-f 3.3 bc ES Ballade c-f 3.5 ab 4.2 ef 3.4 abc Cedro f 2.4 b 3.7 f 2.9 c NK Ravello def 3.1 ab 4.9 c-f 3.4 abc Dumka a-e 3.5 ab 5.9 a-d 4.1 ab Lober a 3.3 ab 4.7 def 4.0 ab DKC a-e 3.6 ab 6.7 a 4.5 ab Eurostar b-f 3.4 ab 5.6 a-e 3.9 abc Nekta ab 3.1 ab 6.4 ab 4.4 ab Zidane abc 3.2 ab 6.0 a-d 4.3 ab KWS 5133 ECO c-f 3.7 ab 5.2 a-e 3.8 abc DKC b-f 3.7 ab 5.8 a-d 4.1 ab Ronaldinio a-d 3.5 ab 6.3 abc 4.4 ab Vitras ab 3.8 ab 6.7 a 4.7 a Koherens a-e 4.1 a 5.6 a-e 4.3 ab KB a-e 3.8 ab 5.6 a-e 4.2 ab Chambord a-e 4.2 a 5,8 a-d 4.6 ab Krabas b-f 3.6 ab 6.1 abc 4.3 ab Mean for Średnio za lata means followed by the same letter do not differ at 5% level of significance (Tukey s multiple range test) średnie oznaczone tą samą literą nie różnią się na poziomie istotności 5% (test wielokrotnych porównań Tukey Our study revealed that in the analysed 3-year period medium-late cultivars (Vitras, Koherens, KB2704 and Chambord) were the most susceptible to damage caused by O. frit larvae, and the least damage was found for early cultivars: KB1903, ES Ballade and Cedro. This may suggest that the plant growth speed at the beginning of vegetation affects the infestation of plants by frit fly. The plant growth speed could have also been determined by the genetic traits of these cultivars and the influence of weather conditions. According to Lisowicz [1984], Szulc and Bocianowski [2014] and Bereś [2014], the population size and harmfulness of frit fly are largely influenced by temperature and humidity during the spring season. Increase in the harmfulness of larvae is particularly stimulated by low temperatures in spring, limiting the intense growth of maize plants. Our study demonstrated that for early-maturing maize cultivars the value of theoretical loss in grain yield was usually lower than the value calculated for medium-late cultivars. This indicates that slower growth at the beginning of vegetation in late-maturing cultivars is a factor limiting severe damage caused by larvae, particularly during periods when weather conditions do not facilitate plant growth. Slower growth of maize plants may contribute to faster allocation of larvae from stems to leaf buds and the growth cone, which, if severely damaged, affect the level of loss in yield (degree of damage 3 and 4 acc. to the adopted scale). It was also found that among the three analysed categories of maize earliness, the susceptibility of cultivars to damage caused by O. frit varied within individual categories, probably because of their genetic potential. Agricultura 14(3) 2015

8 22 P.K. Bereś Studies carried out by other researchers also indicated differences in the susceptibility to O. frit depending on maize cultivar. For example, in Lisowicz [1992] studied 16 different maize cultivars in south-eastern Poland to assess their susceptibility to the pest. He reported that in the analysed 3-year period O. frit larvae damaged from 19.6 to 54.8% of plants and caused a 3.0 to 16.9% theoretical loss in grain yield. Lisowicz found statistically significant differences between the analysed cultivars but did not investigate the effect of earliness on susceptibility to the pest. However, findings by Lisowicz [1992] indicate that frit fly in south-eastern Poland may cause high loss in maize yield when occurring in large populations. On the other hand, studies carried out by Sulewska and Ptaszyńska [2007] in the central-western part of Poland on 6 maize cultivars (FAO ) indicated a relatively low harmfulness of frit fly to maize there. The authors reported that in O. frit larvae damaged on average from 3.1 to 5.4% of plants and demonstrated statistically significant differences in the susceptibility of analysed cultivars to the pest. Early maize cultivars (PR39T68 and Matylda) were damaged to the least degree, and medium-late cultivars (Blask, Anjou 258 and Clarica) were damaged most. The correlation between the earliness of maize cultivar and susceptibility to O. frit was also confirmed in our study. Similar research in central-western Poland was also carried out by Szulc and Bocianowski [2014], who found a significant effect of weather on the harmfulness of frit fly to two medium-early maize cultivars, i.e. ES Palazzo and ES Paroli (FAO ). They reported that low temperatures in spring contributed to the increased harmfulness of O. frit, and found that the stay-green hybrid ES Paroli was less susceptible to feeding larvae, while an increase in the use of nitrogen fertilizer increased the harmfulness of this pest. Differences in the susceptibility to frit fly were also found for cultivars of sweet maize. For example, Waligóra et al. [2008, 2011] carried out studies in the central-western part of Poland and found a significant effect of weather conditions on the harmfulness of O. frit to cultivars of sweet maize. They pointed out that in April feeding of larvae is promoted by higher temperatures and low rainfall, while in May and June by lower temperatures and heavy rainfall. However, Waligóra et al. [2008, 2011] did not demonstrate any correlation between the earliness of the cultivar and its susceptibility to the pest. Research carried out in in Swadzim, near Poznań on 15 cultivars of sweet maize demonstrated that frit fly larvae damaged on average 13.5 to 41.4% of plants, depending on maize cultivar [Waligóra et al. 2008]. Another study carried out in , also in Swadzim, indicated that O. frit larvae damaged on average 12.1 to 23.4% of plants from 9 cultivars of sweet maize [Waligóra et al. 2011]. CONCLUSIONS 1. The study demonstrated that frit fly is one of the major pests of maize in south- -eastern Poland. 2. A significant relationship between the earliness of maize cultivars (FAO number ) and the degree of damage to the plants caused by frit fly was found. Medium- -late cultivars were the most susceptible to damage, and early cultivars were the least susceptible. 3. The degree of damage to maize plants caused by frit fly was largely determined by weather conditions. Acta Sci. Pol.

9 The occurrence and harmfulness REFERENCES Adamczewski, K., Matysiak, K. (2011). Kukurydza. [In]: Klucz do określania faz rozwojowych roślin jedno- i dwuliściennych w skali BBCH. Wyd. III. Instytut Ochrony Roślin, Poznań, Bereś, P.K. (2013). Studium nad doskonaleniem integrowanej ochrony kukurydzy przed zachodnią kukurydzianą stonką korzeniową (Diabrotica virgifera virgifera LeConte) i omacnicą prosowianką (Ostrinia nubilalis Hbn.). Rozpr. Nauk. Inst. Ochr. Roślin Poznań, 29. Bereś, P.K. (ed.), (2014). Atlas szkodników roślin rolniczych. Wyd. Hortpress Warszawa. Bereś, P.K., Pruszyński, G., (2008). Ochrona kukurydzy przed szkodnikami w integrowanej produkcji. Acta Sci. Pol. Agricultura, 7(4), 19-32, Dolinka, B., Zscheischler, J. (1970). On the estimation of the damage caused to maize in the German Federal Republic by the frit fly (Oscinella frit L.) and the possibility of breeding for resistance to the frit fly. Z. Pflanzenkrankh. Pflanzenschutz, 77(9), GUS. (2013). Wyniki produkcji roślinnej w 2012 r. Główny Urząd Statystyczny Warszawa. GUS. (2014). Produkcja upraw rolnych i ogrodniczych w 2013 r. Główny Urząd Statystyczny Warszawa. Kania, C. (1962). Szkodliwa entomofauna kukurydzy obserwowana w okolicach Wrocławia w latach Część II. Pol. Pismo Entomol., Seria B, 1-2(25-26), Lisowicz, F. (1979). Ploniarka zbożówka (Oscinella frit L.) jako szkodnik kukurydzy. Mat. XIX Sesji Nauk. Inst. Ochr. Roślin Poznań, Lisowicz, F. (1984). Noxiousness of frit fly (Oscinella frit L.) to corn in Poland. Z. Pflanzenkrankh. Pflanzenschutz, 91(4), Lisowicz, F. (1992). Szkodliwość ploniarki zbożówki (Oscinella frit L.) dla wybranych mieszańców kukurydzy (Zea mays L.). Prace Nauk. Inst. Ochr. Roślin, XXXIV(1/2), Lisowicz, F. (1994). Występowanie, szkodliwość oraz metody zwalczania ploniarki zbożówki (Oscinella frit L.) na kukurydzy. Biuletyn IHAR, 191, Lisowicz, F. (1996). Teoretyczne i praktyczne podstawy zastosowania metod integrowanych w ochronie kukurydzy przed szkodnikami. Prace Nauk. Inst. Ochr. Roślin, 36(1/2), Lisowicz, F. (2001). The occurrence of economically important maize pests in south-eastern Poland. J. Plant Prot. Res., 41(3), Lisowicz, F., Tekiela A. (2004). Szkodniki i choroby kukurydzy oraz ich zwalczanie. [In]: A. Dubas (ed.), Technologia produkcji kukurydzy, Wieś Jutra Warszawa, Matyjaszczyk, E. (2013). Plant protection in Poland on the eve of obligatory integrated pest management implementation. Pest Manag. Sci., 69(9), Matyjaszczyk, E. (2014). Prevention methods for pest control and their use in Poland. Pest Manag. Sci., DOI: /ps Meissle, M., Mouron, P., Musa, T., Bigler, F., Pons, X. et al. (2010). Pests, pesticide use and alternative options in European maize production: current status and future prospects. J. Appl. Entomol., 134(5), Mrówczyński, M. (ed.)., (2013). Integrowana ochrona upraw rolniczych. Tom II. Zastosowanie integrowanej ochrony. PWRiL Poznań. Sulewska, H., Ptaszyńska, G., (2007). Podatność odmian kukurydzy na ploniarkę zbożówkę (Oscinella frit L.) i omacnicę prosowiankę (Ostrinia nubilalis Hbn.). Prog. Plant Prot./Post. Ochr. Roślin, 47(4), Szulc, P., Bocianowski, J., (2014). Susceptibility of maize hybrids (Zea mays L.) to frit fly (Oscinella frit L.) under conditions of diversified nitrogen content in the soil and different types of nitrogen fertilizers. Acta Sci. Pol. Agricultura, 13(2), 63-77, Waligóra, H., Skrzypczak, W., Szulc, P., (2008). Podatność odmian kukurydzy cukrowej na ploniarkę zbożówkę (Oscinella frit L.) i omacnicę prosowiankę (Ostrinia nubilalis Hbn.). Prog. Plant Prot./Post. Ochr. Roślin, 48(1), Waligóra, H., Weber, A., Skrzypczak, W., Szabelska, A., (2011). Wpływ warunków pogodowych na uszkodzenia wybranych odmian kukurydzy cukrowej przez ploniarkę zbożówkę (Oscinella frit L.). Nauka Przyr. Technol., 5(2), #10. Agricultura 14(3) 2015

10 24 P.K. Bereś WYSTĘPOWANIE I SZKODLIWOŚĆ Oscinella frit L. (DIPTERA: CHLOROPIDAE) DLA ODMIAN KUKURYDZY UPRAWIANYCH NA ZIARNO W POŁUDNIOWO-WSCHODNIEJ POLSCE Streszczenie. Badania nad wieloletnim występowaniem ploniarki zbożówki (Oscinella frit) na kukurydzy uprawianej na ziarno wykonano w latach w południowo- -wschodniej Polsce w miejscowości Krzeczowice. W analizowanym okresie larwy O. frit uszkodziły na średniowczesnej odmianie kukurydzy (FAO 240) od 3,5 do 42,2% roślin (średnio 25,2%), powodując teoretyczne straty w plonie ziarna w wysokości od 0,4 do 8,1% (średnio 4,5%). Badania nad podatnością kukurydzy na żerowanie ploniarki zbożówki wykonano w latach na 18 odmianach należących do trzech klas wczesności: wczesne (FAO ), średniowczesne (FAO ), średniopóźne (FAO ). W analizowanym trzyleciu larwy O. frit uszkodziły średnio na badanych odmianach od 20,4 do 32,3% roślin, powodując średnią teoretyczną stratę w plonie ziarna w wysokości od 2,9 do 4,7%. Stwierdzono statystycznie istotne różnice w podatności badanych odmian na uszkodzenia powodowane przez O. frit. Istotnie bardziej uszkadzane przez ploniarkę zbożówkę były odmiany średniopóźne w porównaniu z odmianami wczesnymi. Słowa kluczowe: klasa wczesności, odmiany, ploniarka zbożówka, podatność, Polska, Zea mays Accepted for print Zaakceptowano do druku: For citation Do cytowania: Bereś, P.K. (2015). The occurrence and harmfulness of Oscinella frit L. (diptera: Chloropidae) to maize cultivars cultivated for grain in south-eastern Poland. Acta Sci. Pol. Agricultura, 14(3), Acta Sci. Pol.