The influence of Fusarium ear infection on the maize yield and mycotoxin content (Transylvania-Romania) Maize is the host for a large number of pathogens, which invade all of its organs from the germination until being harvest, ear and grain infection often persistent even during storage. Diseases, through their symptoms reduce significantly the quantity and the quality of yield, estimated between 7-17% but, in the favorable years for this disease, they can be much greater. Fusarium diseases reduce yield value and quality by massive accumulation of Fusarium mycelium biomass (about 85%) on grain and ears and by mycotoxin contamination such as deoxynivalenol (DON), zearalenone (ZEA) and fumonisins (FUM). In this paper are presented aspects regarding the reaction of some maize hybrids under Fusarium spp. natural and artificial infections; the effect of Fusarium ear infection on yield, grain chemical composition, and mycotoxin content; the correlation between ear rot disease degree and yield ability, starch, protein and fat content. ANOVA evidenced the significant influence of experimental factors: infection conditions with Fusarium spp., maize genotypes, and their interaction on expression of the disease degree, yield capacity, protein, starch, fat and DON content. Average yield losses ranged between 7,0-9,3% during the experimental period. The hybrids Turda Star and Turda Favorit were more resistant to Fusarium ear rot, and Turda 165 was the most susceptible one. The artificial infection of ear with Fusarium spp. determined significantly decrease of starch and fat content and increases the protein and DON content for the most part of maize hybrids. Between rot diseased kernels and DON content a positive correlation was determined.

The fusarium ear rot caused by pathogens belonging to Fusarium genus is one of the most important diseases responsible for high economic losses, resulting from the decline of the production’s quantity and quality. The objective of the present study was the identification of sources of cytoplasm that convey resistance to fusarium ear rot within certain inbred isonuclear lines. Twenty five maize inbred lines: 20 isonuclear inbreds (obtained by transferring the nucleus of five elite inbred lines on four different cytoplasms) and five lines using the original cytoplasm were studied in three experimental years 2012, 2013 and 2014. The analysis of variance for fusarium ear rot showed the very significant influence of factors years and nucleus and the significant action of the cytoplasm. The resistance to fusarium ear rot of each isonuclear line was compared to the line with original cytoplasm, over the three years of the experiment. Genetic variability within isonuclear groups regarding the resistance to fusarium ear rot was observed. The greatest difference in the degree of attack on the maize cob in comparison with the original cytoplasm (-4.92%), was noted for isoline TB 243 x TB 329, which showed a very significantly negative difference. Changing cytoplasm resulted in genotypes with a good resistance to the Fusarium spp. attack; therefore the use of these genotypes is recommended in creating of new hybrids.

The paper presents data about wheat pest attack in Transylvania in the last 10 years, under the different climatic, phenological and technological conditions, with details of the correlations of the climatic factors with the bio-ecology of the species or pest groups. Such data may be important for modelling and forecasting wheat pest attacks. The climatic warming, represented strong environmental factors (R2 = 0.43), which led to changes in the species structure, favouring the development of the populations of a narrow spectrum of species becoming dominant and dangerous by numerical increases. In the years 2006-2015, the eudominance of thrips (58%), the dominance of aphids (14%) and of wheat flies (12%), the subdominant species of Chrysomelidae and the increase of entomophagus abundance were revealed. In the year 2016, the weight of the dominant groups of wheat flies (25%), aphids (21%), leafhoppers (18%), thrips (17%), of the subdominant group of Chrysomelidae (10.6%) and cereal bugs (4.5%) increased. Changes in entomocenotic interactions phytophagusentomophagus, changes in pest dynamics, and of optimal moments for treatments important in the development of integrated pest control systems, have occurred in wheat crops. In the conditions of the area, the annual abundance of entomophagus is determined by the annual abundance of phytophagous insects, as expressed by a positive correlation (R2 = 0.464 and D% = 46.4%). Under the conditions of the last 10 years, the annual ratio of the number of phytophagous / entomophagus fluctuated between 2.35 and 12.42. The size of the phytophagous / entomophagus ratio was strongly correlated with the increase of the average annual temperatures, with a percentage determination coefficient D% = 15.5%, having an optimum of the interactions at values of 6.3 phytophagous / 1 entomophagus, and less well correlated with the annual precipitations. These changes in wheat entomocenoses, the biological potential accumulated over the last 10 years and at the level of 2016 indicate the importance of adapting pest control strategies, which should include preventive methods (respecting the optimum sowing time, agro-technical and phytosanitary methods), insecticide treatments on seed and on vegetation, at optimal application times for the groups of pests whose attacks overlap, respectively the first treatment in the spring, no later than the end of tillering, for wheat flies, leafhoppers, Chrysomelidae etc.; the second treatment at the phenophase of flag leaf stage and ear appearance, for thrips, aphids, bugs etc.; and other treatments at warning. Given the importance of entomophagous arthropod fauna in limiting wheat pests it is necessary to protect and use the auxiliary entomophagus, flora biodiversity involved in achieving the productivity and stability of wheat crops.

Abstract. Wheat is one of the oldest cultivated plants and most important food plant, the wheat flour bread is the basic food for majority of world population. At the same time the corn crop is affected by many diseases that cause quantitative and qualitative losses. From the many diseases common to the wheat culture, fusarium head blight, produced by species of the Fusarium genus, is appreciated in most parts of the world, as one of the most damaging disease. In addition to losses of production, 10-2 percent in favourable conditions, the flour for bread that came from crops affected by Fusarium is inferior in terms of quality, the bread has low volume and low protein content. The studies conducted have shown the impact of Fusarium infection on dough properties and additional properties for baking therefore a decrease in flour yield and also an increase in ash content in the flour obtained from grain infected with Fusarium observing also a darker colour and an unpleasant odor of flour, protein content and wet gluten increase or decrease after Fusarium infection. Determination of quality parameters, protein, ash and gluten and the production of four wheat varieties in different testing conditions. Study of the Fusarium infection effect on quality parameters and yield was achieved through experiences located in three repetitions. There have been tested four different variants uninoculated - untreated, inoculated - treated,  inoculated - untreated, uninoculated - treated on four varieties of wheat Ariesan, Andrada, Apulum and Dumbrava. The artificial infections with Fusarium spp. were made by spraying method according to Ceapoiu and Floare Negulescu,  ( 1988 )  and the treatments applied on vegetation were done with fungicides Nativo and Prosaro 460 EC. The testing modality influenced the behaviour of the varieties in terms of production and quality parameters obtained. For all varieties studied, in the variants were applied, vegetation treatment, even though artificial inoculation that have been made high productions were obtained.

The use of meta-models approach as component of the prevention strategy against different pathogens attack, specific for vegetal cultures, receives an increasing interest. Due to the importance of  the  climatic  influence  upon  pathogens  action,  almost  all  these  approaches  use  the  inputs  from meteorological stations placed in field. Another important component of such a system is represented by  a  specific  software  program  used  for  estimation  of  virtual  geographical  distribution  of  target pathogen/pathogens.  This  article  aims  to  emphasize  the possibility  of  using  the  meta-models  for predicting Phytophtora infestans Mont.  de  Bary  attack. The research was  carried  on  during  spring - autumn 2012 in a potato field located in Jucu village, on the experimental field of the UASMV Cluj - Napoca.  Climatic  conditions  (temperature  and  rainfall  regimen)  and  attack  degree  were  monitored using  a  meteorological  station  placed  on  the  field,  and  observations.  Rainfall  regimen  and  average daily  temperature  were taken  into  consideration,  in  approaching  the  multiregression  model  with  tow inputs. The  statistical  data  processing  was  performed  with  STATISTICA  7.0  v.  programme.  The analysis  of  variance  (ANOVA)  applied  to  the  interaction  between  attack  degree  of Phytophthora infestans  Mont.  de  Bary  in  potato -  temperature -  rainfall  allows  us  to  use  the  proposed multiregression  model  (F  =  7,892,  p  <  0.001).  The  multiregression  analyze  emphasize  a  strong multiple correlation coefficient of 0.895 which accounts from 81.10% of the predicted attack degree. The  regression  line,  Y  =    24.311  +  2.813X1  +  0.122X2  show,  in  climatic  conditions  specific  for  the experimental  year  2012,    the  bigger  influence  (more  than  twice)  of  the  thermic  conditions  on  the Phytophthora infestans Mont. de Bary attack degree in potato, compared to rainfall influence on the same pathogen.Obtaining the regression parameters allows us to build a meta-model for predicting the evolution of the Phytophthora infestans Mont. de Bary attack degree in potato, reliable in a high share, 81.10%, respectively, and presenting the advantage that it gives comparable results, which contribute to increase the consistency of assessments patterns.