No abstract

No abstract

In this paper, author collective present results and methodology of the insecticides testing against maize leaf weevil, in laboratory conditions. Year by year at NARDI Fundulea, in field conditions, it has tested insecticides used both like seed and vegetation treatment for control ling of the maize leaf weevil. Because climatic conditions from the spring are not favorable for this pest every year, laboratory testing is one of the best methods for evaluate of the insecticides used like seed treatment. At eight days after insects are added in the pots with maize plants, highest adults mortality and lowest attack intensity has registered in case of plants emerged from the seeds treated with products on base of thiametoxan  ( Cruiser 350 FS ) , clothianidin  ( Poncho 600 FS )  or thiametoxan+teflutrin  ( Force Zea ) . In case of seeds treated with product on base of imidacloprid  ( Nuprid 600 FS 8,0 l/t ) , even if the insects mortality was lower, the attack intensity has low values. All plants from the untreated variant were destroyed. At treated variants, saved plants percent were at least 90 %. Seed treatments provide a satisfactory protection of the maize plants, in first vegetation stages against maize leaf weevil.

In the last years sunflower become one of the most important crops in Romania. The most of the surface cultivated with sunflower from our country is located in south and south-east and, in many cases, sunflower is cultivated after maize. As result the attack of the maize leaf weevil (Tanymecus dilaticollis Gyll) at sunflower plants has increasing. The attack is dangerous when sunflower plants are in first vegetation stages . Similar with maize crop, sunflower seeds treatment with neonicotinoids were generalized after 2007. As result of the EU directive 485/2013, no active ingredients remain available for sunflower seeds treatment, against T. dilaticollis, in Romania. The researches from the last years were orientated for finding of the possible alternatives for seed treatments, in eventuality of permanent ban of neonicotinoid insecticides, after 2018. Because of the variability of climatic conditions from the field, during spring period, researches concerning effectiveness testing of sunflower seed treatments, in green house conditions, using high pest pressure is a good method to evaluate influence of the different active ingredients to control T. dilaticollis adults. In this experiment it has tested three doses of cyantraniliprole active ingredient (7.5, 10.0 and 12.5 l/to) and three neonicothinoid active ingredients (imidacloprid, clothianidin, thiamethoxam). Sunflower seeds were placed in plastic pots. After plants emergence the insects were added in pots. At each pot it has added 20 adult insects, collected from the field. Each day, it has recorded insect mortality. At 8 days from the start of the experiment, it has assessed attack intensity of the adult insects on sunflower plants. The attack was evaluated using a scale from 1 (plant not attacked) to 9 (plant complete destroyed). In conditions of high pest pressure (4 insects/plant) the attack intensity of T. dilaticollis at sunflower plants was ranged from 3.35 in case of variant treated with clothianidin and 8.50 in case of untreated plants. Lower attack intensity of the pest at sunflower plants it has registered in case of variants treated with imidacloprid and thiamethoxam (I=3.58 and 3.50). Plants emerged from the untreated seeds were destroyed by the insects, at 8 days from the start of the experiment.

Pathogenicity and aggressiveness vs. wheat of 30 new Fusarium accessions, primarily F. graminearum, obtained from random naturally infected grain samples of bread wheat, durum wheat and triticale collected across Romania, phenotypically and by molecular tools has been investigated. A large variation of this trait, expressed as reduction of coleoptiles length (% of control), in seedling stage, on average over three varieties, ranging from 2.1 to 30.9 % was registered. Point field inoculations at anthesis of 90 Fusarium isolate x wheat varieties combinations, revealed also the variability of several components of aggressiveness: severity (14.4-64.8%), AUDPC (104.9-527.1), and FDK 8.1-43.7%, respectively.Molecular techniques allowed identification of Fusarium species and the analysis of polymorphism within fungal isolates. Moreover, the presence of TRI 5 gene involved in DON biosynthesis was detected in the majority of isolates.Similarity between records obtained in seedling and adult stage for the most aggressive of Fusarium isolates, suggests that phenotypic selection in conjunction with molecular tools could be a reliable method to select the appropriate pathogen strains for breeding of resistance.