Testing effectiveness of the maize seeds treatment concerning maize leaf weevil (Tanymecus dilaticollis Gyll) control, in laboratory conditions

Maize leaf weevil (Tanymecus dilaticollis Gyll) is an economically important pest of maize crop in south and south-east of the Romania. The insect is favored by high temperature and drought when maize plants are in first vegetation stages. In this assessment it has studied effectiveness of some insecticides used like seed treatment in laboratory conditions, in plastic pots sowed with treated and untreated maize seeds. Each pot was infested with adult insects collected from the field after plant emergence. Insects mortality were higher in case of seeds treated both with thiametoxan (Cruiser 350 FS) and clothianidin (Poncho 600 FS) active ingredients. Seeds treated with tiacloprid active ingredient (Sonido) provide lower mortality values. Attack intensity was lower in case of seeds treated both with thiametoxan (Cruiser 350 FS) and clothianidin (Poncho 600 FS) active ingredients and higher in case of treated seeds with tiacloprid active ingredient (Sonido). Seeds treatment provides satisfactory protection for maize plants in first vegetation stages against Tanymecus dilaticollis. Bioassays in laboratory conditions are a complementary method with field testing and provide useful information regarding insect behavior

TESTING OF THE NEW ACTIVE INGREDIENTS FOR CONTROLLING OF THE OSTRINIA NUBILALIS HBN AT MAIZE CROP, IN CONDITIONS OF ARTIFICIAL INFESTATION, AT NARDI FUNDULEA

In this paper, author collective present preliminary results of new active ingredients testing for vegetation treatment against European corn borer at maize crops. Maize plants were artificial infested witch Ostrinia nubilalis egg batches produced in laboratory conditions, from insects reared consecutive generations, using same artificial diet. Climatic conditions from summer period were favorable for pest evolution in 2016 comparative with 2014. At untreated maize plants, average number of larvae per plant was 3.03 in 2014 and 14.70 in 2016 while average length of the cavities per plants was 13.41 cm in 2014 and 20.18 cm in 2016. At treated variants, in climatic conditions of the summer of 2014 and 2016, higher effectiveness was registered in case of higher dose of indoxacarb active ingredient and chlorantraniliprole active ingredient, in dose of 150 and 200 ml p.c./ha

Green peach aphid (Myzus persicae) can be a serious pest problem for oilseed rape crop, in the south-east of Romania

In this paper, it has reported a high attack of the green peach aphid (Myzus persicae), in late autumn of the year 2018, at oilseed rape crop, in the south-east of Romania. This pest has a wide range of host plants, attacking more than 240 species from 64 different botanical families. The evolution of green peach aphids at oilseed rape crop, during autumn, was assessed in this paper. A field experiment was carried out at NARDI Fundulea, both in 2017 and 2018. It has assessed untreated and treated seeds variants with systemic insecticides. Also, it has recorded percentage of parasitized aphids by Aphidius spp. and Praon spp. In the weather conditions from autumn of the year 2017, green peach aphids density at oilseed rape crops was insignificant with a maximum of 2.25 aphids/leaf at untreated plants and 0.38 aphids/leaf at plants emerged from treated seeds. However, in 2018 it has registered a high density of this pest at oilseed rape crop with a maximum of 243.25 aphids/leaf at untreated plants and 29.38 aphids/leaf at plants emerged from treated seeds. In weather conditions of the year 2018, in the experimental field from NARDI Fundulea, highest population amount of green peach aphids at untreated oilseed rape plants it has recorded in late autumn, on 12 November. Possible explication for this is because of higher temperatures and drought recorded both in October and the first half of November. At the same time, in autumn of 2018, parasitized aphids percent was 5.15 % at untreated variant and between 4.74 and 5.00 % at treated variants. This situation occurred in autumn of 2018, in the south-east of Romania must be a warming for the farmers for the following years. Increasing the temperature and drought can have an effect of increasing the attack of aphids at oilseed rape crops, in autumn

Is biological control a solution for maize plants protection against maize leaf weevil (Tanymecus dilaticollis Gyll) attack in climatic conditions specific from South-East of the Romania?

Maize leaf weevil (Tanymecus dilaticollis Gyll) is the most dangerous pest of the maize, in south and south-east of the Romania. The attack is dangerous when maize plants are in first vegetation stages (plants emergence-four leaf stage, BBCH 10-BBCH 14), in some cases maize crop can be total destroyed. Each year, in maximum favorable areas for this pest, there is attacked, with different intensity degrees, one million hectares cultivated with maize. Seeds chemical treatment with systemic insecticides represented the most efficacy method of maize crops protection against attack of this pest, in climatic conditions specific for south east of the Romania. As result of the EU directive 485/2013, starting from year 2014, the use of the neonicotiond insecticides (imidacloprid, clothianidin, thiametoxan active ingredients) for spring crops seeds treatment, was restricted. However, in perioad 2014-2018, Romania obtained derogations for use of these insecticides for seed treatment of maize and sunflower crops. As result of EU states vote, in 27 April, 2018, it has decided total ban of using of this three active ingredients from neonicotinoids class at all field crops, starting from 2019. As result, in Romania, at maize crop, no active ingredient will remain available for seed treatment against maize leaf weevil attack. In this paper there were presented results of a three-year study, effectuated at NARDI Fundulea, concerning the efficacy of the biological insecticides, used both at seed treatment and foliar spraying (spinosad active ingredient and neem oil) comparative with seed treatment with imidacloprid active ingredient (600 g/l). In the three study years, the lowest attack level of the Tanymecus dilaticollis at maize plants it has registered in case of the variant with seeds treated with imidacloprid. In climatic conditions specific from south-east of Romania, in period 2016-2018 there weren’t statistical differences (p<0.5) between control (untreated) variant and variants treated with biological products, both like seed treatment and foliar spraying

PRELIMINARY RESULTS CONCERNING TESTING OF THE NEW ACTIVE INGREDIENTS USED LIKE MAIZE SEED TREATMENT FOR CONTROLLING OF THE TANYMECUS DILATICOLLIS GYLL IN LABORATORY CONDITIONS, AT NARDI FUNDULEA

Maize leaf weevil (Tanymecus dilaticollis Gyll) is an economically important pest of the maize crop in south and south-east of the Romania (Cristea et al., 2004). Recent data from literature suggest that higher attack of this pest occur in south-west of the country too and some counties from Moldova region (Popov et al., 2003, 2005, 2007). Same author mention that every year, 1.000.000 ha with maize from the favorable areas are affected by the insect attack. T. dilaticollis is dangerous when maize plants are in first vegetation stages, between plant emergence and four leaf stage (Paulian, 1972). In some cases,maize plants can be destroyed because of the insect attack before plants arrive at soil surface (Barbulescu et al., 2001). At a density between 25 and 30 insects/m2, average yield losses were 34 % (Paulian, 1979). In last decades, several studies from Romania and other countries from South-East of Europe make in evidence that seed treatment is one of the most effective method for protect maize young plants against pests attack, such as T. dilaticollis (Voinescu, 1985; Barbulescu et al., 2001; Krusteva et al., 2006; Keszthelyiet al., 2008; Popov et Barbulescu, 2007; Čamprag, 2011, Trotus et al., 2011). From middle of the years `90 it has tested insecticides from neonicotinoid class for maize seeds treatment against main pests of this crop, especially when plants are in first vegetation stages (Popov et Barbulescu, 2007). Higher effectiveness of these active ingredients was mentioned in different communications (Barbulescu et al., 2001; Popov, 2002; Vasilescu et al., 2005). As result of EU directive 485/2015, from 1 December the use of neonicotinoidinsecticides for seed treatment of the spring crops, including maize, was restricted for two years (Official Journal of the European Union, 2013). After this directive no insecticides remain available for maize seed treatment against T. dilaticollis in Romania. Although it has obtained temporary authorizations for use of the neonicotinoid insecticides like seed treatment at maze crop in spring period, both, in 2014 and 2015, it is necessary to testing new insecticides for evaluate there effectiveness for controlling of the maize leaf weevil. These types of assessments were organized in field conditions, in spring period (Paulian 1972; Voinescu 1985; Barbulescu, 2001; Vasilescu, 2005). However climatic conditions from spring were variable from one year to another. In years with reduced rainfall level in the spring, the attack of T. dilaticollis on maize untreated plants was maximum or almost maximum, while in years with higher rainfall level the attack of this pest on maize untreated plants was lower (Popov et al., 2006). At NARDI Fundulea, Paulian (1972) develop a laboratory method for evaluate effectiveness of seed treatments, where maize emerged plants are placed in conditions of high attack pressure. Barbulescu A. et al. (2001) tested the efficacy of the maize and sunflower seeds treatment with neonicotinoid insecticides in laboratory conditions, using a pest density from four to seven adult insects per plant. In Hungary, Keszthelyi et al. (2008) study effectiveness of both, seed and soil treatments, on three soils type, using isolators, previously sown with corn. In Bulgaria, Draganova S. (2012) testing effectiveness of some Beauveria bassiana isolates for biological control of T. dilaticollis adults in laboratory conditions. The aim of the authors collective is testing different insecticides used like seed treatments, both in laboratory and field conditions, for find alternative at the neonicotinoids treatment in eventuality of permanent ban of these substances in EU. In this paper are presented preliminary results of testing seven active ingredients from three different insecticide classes (pyrethroids, neonicotinoids and ryanoids), in laboratory conditions, using pest high pressure

Economic advantages of using bacterial biopreparations in agricultural crops

The ecological, genetic, biological approach proposed by agricultural specialists in order to protect plants and crops has a role in reducing the impact of pests through the process of selection and improvement of genetic resources in the processes of planting, development and introduction of biological means to combat pests in agricultural ecosystems. The strategies proposed by the specialists in the agricultural field aim not at the total extermination of the pests from the agricultural crops but at keeping the pest populations at the optimal damage threshold. The most important advantages of these biological processes are those of the evolutionary stability of the crop systems, the ecological stabilization of the pest and crop populations as well as the assurance of a superior quality of the resulting agricultural products.The present paper aims to present the main advantages of using bacterial biopreparations in agricultural ecosystems (research conducted in agricultural research stations in Romania), reducing soil pollution, environmental crops, use of alternative fertilization and cultivation technologies as well as obtaining additional, ecological productions.The aim of this paper is to present the economic advantages of using bacterial biopreparations in agricultural research and development stations, reducing costs in agriculture and the processes that these bacterial biopreparations have on the agricultural ecosystem, the environment and humans and animals

Behavior of some maize hybrids to the European corn borer (Ostrinia nubilalis Hbn) attack, at NARDI Fundulea, 2013-2014

In this paper there were presented some results concerning testing of 18 maize hybrids to evaluate reaction at European corn borer attack (Ostrinia nubilalis Hbn.), in climatic conditions of the years 2013 and 2014, at NARDI Fundulea. Maize plants were artificial infested with ECB egg batches, produced in laboratory conditions, by rearing insects, successive generations, on continuous flux, using same artificial diet. Also, it has evaluated maize plants in conditions of ECB natural attack. Total number of egg batches obtained in laboratory was 133550 in 2013 and 159116 in 2014. Climatic conditions from summer period, registered at NARDI Fundulea, were more favorable for pest attack in 2014 comparative with 2013. Average natural attack frequency of the O. nubilalis at maize hybrids from the experiment was of 43.3 % in climatic conditions of the year 2013 and 79.4 % in climatic conditions of the year 2014. In case of artificial infestation of maize plants with ECB egg batches, average attack frequency was 91.7 % in 2013 and 95.5 % in 2014. Attack intensity was higher in 2014 comparative with 2013, both, at plants not infested and plants artificial infested. In both years, the differences between hybrids reaction to the attack of European corn borer were higher in case of artificial infestation, comparative with natural attack. Higher attack values, in both years, it has registered at Milcov, Paltin and F 59-09 hybrids while lower attack it has registered in case of F 475 M hybrid. Some maize hybrids have different reaction to ECB attack in 2013 comparative with 2014

Preliminary study concerning climatic conditions influence from winter season on maize leaf weevil (Tanymecus dilaticollis Gyll) attack

Maize leaf weevil (Tanymecus dilaticollis Gyll) is the main pest of the maize crops in south and south-east of the Romania. In this paper, authors collective present preliminary results of a study concerning influence of the winter conditions on attack of T. dilaticollis. It has analyzed the temperatures from winter (December-February) and attack intensity of the studied pest at maize untreated plants, in spring period. Pest attack was rated when maize plants were in four leaf stage (BBCH 14) on a scale from 1 (plant not attacked) to 9 (plants complete destroyed). During the time, at NARDI Fundulea, winters were variable, from one year to another. The attack of T. dilaticollis at maize untreated plants registered in springs followed after cold winters was low in 1999 (I=4.3), high in 2003 and 2012 (I=7.8 and 6.7) and moderate in 2011 (I=5.8). The attack registered in springs followed after warm winters was high in 1989 (I=9.0) and 1995 (I=8.4), while in year 2001, followed after one of the warmest wither of the century, the attack of the maize leaf weevil at untreated plants was low (I=4.8). There were no correlation between temperatures registered during winter season and attack of T. dilaticollis at maize plants registered in spring. The most important for pest attack are the climatic conditions from period when maize are in first vegetation stages (BBCH 10-14). Results of the study effectuated at NARDI Fundulea make in evidence that low rainfalls level and high temperatures from this period favor pest attack