Claudia Regina Dias-Arieira

Reaction of vegetables and aromatic plants to Meloidogyne javanica and M. incognita

For this research we used 15 day-old seedlings which were transplanted to 2 L pots and inoculated with 4,000 nematode eggs plus juveniles (J2). After 60 days, the root systems were removed and the number of galls and eggs evaluated and used to calculate the nematode reproduction factor (RF). The tomato cv. Santa Cruz was used as a susceptible control. The experimental design was completely randomized, with six replications. Averages were compared using the Tukey or Scott-Knott test at 5%. For lettuce, Salad Bowl (Mimosa type), Elizabeth and Elisa (Lisa) and Vera cultivars (crisphead), the number of galls and the RF for M. javanica were statistically higher than for the control, whereas, for the other vegetable crops, the highest number of galls and eggs were found in chicory and basil. The highest susceptibility to M. incognita was observed in Mimosa lettuce cv. Salad Bowl, chicory cultivars, parsley cv. Grauda Portuguesa and basil. Marjoram exhibited no M. incognita galls.

Resistance inducers in the control of root lesion nematodes in resistant and susceptible cultivars of maize

Pratylenchus brachyurus stands out among the major importance nematodes for the national agriculture, due your difficulty of control. Thus, the study aimed to evaluate the efficiency of resistance inductors in the nematode management in resistant and susceptible maize. It was studied the inductors acibenzolar-S-metil, Ecolife™ and manganese phosphite. The experiment was conducted in a factorial arrangement (2 × 4) composed for two maize genotypes (resistant and susceptible to nematode). Each inductor was applied, singly, seven days and one day before inoculation and seven days after inoculation to nematode. Untreated plants were used as control. The inductor Acibenzolar-S-metil was efficient to reduce the nematode population in both genotypes. Ecolife™ promoted the nematode reduction in susceptible genotype while the results were variable for manganese phosphite. In general, the inductors showed no significant effect on plant development and the same factor mainly affected by genotype.

Agro industrial waste and sewage sludge can control Pratylenchus brachyurus in maize

Abstract If agro industrial byproducts are not properly disposed of, they can cause environmental pollution. These materials are rich in nutrients and could be useful in agriculture, with a possible role in the nematodes control, especially Pratylenchus spp., one of the worlds most pernicious species. Therefore, the aim of this study was to evaluate the effect of waste produced in the northeast of Parana State in controlling Pratylenchus brachyurus. Maize plantlets were transplanted to pots containing infested soil. After 90 days, the shoot was discarded and each pot top-dressed with the following: sewage sludge, vinasse, filter cake, poultry litter, or manipueira (liquid extract of cassava root). Maize seedlings were again transplanted to the pots where they remained for 70 days. The plants were then collected for evaluation in terms of height, fresh shoot, dry weight, root fresh weight, and number of nematodes/g root and per 100 cm3 soil. All treatments were effective in controlling nematodes. Enhanced plant development was observed after treatment with poultry litter. We therefore conclude that agro industrial waste provides a fresh alternative for controlling P. brachyurus.

Resíduos de frutos de pequi no controle do nematóide das galhas em tomateiro

ABSTRACT Pequi fruit waste in the control of root-knot nematodes in tomato The exocarp and external mesocarp of pequi fruit are discarded during the extraction of internal mesocarp which is the commercial part used as food. The objective of this research was to study the use of aqueous extract and of pequi ground-powder to the control of root-knot nematode ( Meloidogyne javanica ). From ground pequi fruit exocarp and external mesocarp were obtained the aquaeous extract and powder. Five doses of aquaeous extract (0.0; 2.5; 5; 10 or 20%) were evaluated on root-knot nematode J2 (second stage juvenile) hatching and mortality. The assays were carried out in entirely randomized design with 10 replications. The hatching assay was set in Petri plates with 800 nematode eggs and 10 mL of different doses of extract. During 14 days we counted the number of hatched juveniles under optical microscope. The mortality assay of root-knot nematode was evaluated putting 100 μL of each dose of extract plus 20 μL of supension containing 20 J2 in each cell Elisa plate. After 24 h was counted the number of live and dead juveniles. The pequi powder was tested in tomato plants in greenhouse in four doses (0; 7.5; 15 or 30 g/4 kg of soil) in randomized blocks design with 10 replications per treatment. The pequi powder was incorporated to the soil seven days before transplanting and nematode eggs inoculation was carried out after transplanting. After 40 days we evaluated the number of galls, egg masses, eggs/root and J2 per 200 cm

Host status and phenotypic diversity of rice genotypes in relation to Pratylenchus brachyurus resistance

The aim of this study was to assess the susceptibility of rice genotypes to Pratylenchus brachyurus and investigate the inheritance of resistance in the crop. Two experiments were conducted under controlled conditions, using naturally infested soil. Twenty-six rice genotypes were assessed, with maize used to show the susceptibility pattern. The maize was cultivated for 90 days and the initial nematode population was determined. Then, rice genotypes were cultivated, and the final nematode population and the reproduction factor (RF) were estimated 90 days after germination. All genotypes were susceptible to P. brachyurus in the two experiments but only one showed statistical differences, indicating variation in susceptibility, and genotypes Linhagem L03-107 and Cateto Amarelo scored higher than the control genotype, with RF of 8.80 and 9.48, respectively. Inheritance of resistance was poorly influenced by genotype genetics. Cluster analysis allowed the identification of five different groups of genotypes but there was low genetic variability among the genotypes.

Penetration of Pratylenchus zeae in antagonistic plants

Pratylenchus zeae Graham is one of the most important nematode species found in sugarcane and has been reported in the main sugarcane-producing regions of Brazil, especially in areas of commercial production in the state of São Paulo (Novaretti et al., 1998, Dinardo-Miranda et al., 2003), in the northeast region (Moura et al., 2000) and in Paraná (Severino et al., 2010). Due to the scarcity of plants resistant to root-lesion nematode and limitations regarding the use of chemical control, crop rotation is becoming increasingly important. Thus, the use of leguminous plants as a green manure is crucial as it promotes, among other benefits, improvements in the physical and chemical conditions of the soil (McSorley & Gallaher, 1994). An experiment was conducted in a glasshouse at Universidade Estadual de Maringá, campus Regional de Umuarama (State University of Maringa, Umuarama Regional Campus) in January 2014, with minimum and maximum temperatures of 20.2 and 32.4°C, respectively. The species assessed in this experiment were crotalaria (Crotalaria spectabilis), dwarf pigeon pea (Cajanus cajan), velvet bean (Mucuna aterrima), jack bean (Canavalia ensiformis) and stylosanthes (Stylosanthes capitata + S. macrocephala), with maize (Zea mays) cv. IPR 114 as control. The seedlings, produced in the same manner, were transplanted into 500 ml plastic containers of the

Boron and zinc inhibit embryonic development, hatching and reproduction of Meloidogyne incognita

ABSTRACT Nematodes have difficult control and complex handling, but considering the physiological and biochemical changes that micronutrients promoting in plants, there is possibility that the supply with these chemicals increases the resistance of plants against nematodes. Thus, the present study aimed to assess the effect of the application of boron and zinc on the reproduction of Meloidogyne incognita, embryonic development and juvenile nematode hatching. Nematode reproduction was evaluated in tomato plant inoculated with 2000 eggs and treated in the aerial part with boron or zinc at the following doses: 0, 1/2, 1×, 2× and 4× the manufacturers recommendation (100 and 30 g/L, respectively), with the plants assessed 60 days after inoculation. For assessment of embryonic development and juvenile hatching, 1 mL nematode suspension was placed in Petri dishes containing 9 mL of the same doses of boron and zinc, and assessment occurred four and eight days after incubation. Results obtained showed that boron controlled nematode population at the dose of 400 g/L and promoted juvenile hatching when used at maximum dosage on the eighth day. Zinc reduced the number of galls and the number of eggs at the dose of 60 g/L, but did not exhibit direct effect on nematode.

Agronomic performance of maize with different fertilizers in winter crop succession

The aim of this study was to evaluate the effect of temperate climate plant species and two different types of fertilizer on the yield components related to summer maize crop productivity in an area with a history of 5 years of soybean/black oat succession cropping in a no-tillage system in ArenitoCaiua, Northwestern Parana State, Brazil. The experiment was conducted in split blocks, with 6 blocks and 16 treatments (8 winter crops and 2 types of fertilizer). The maize hybrid used was DKB 390PRO. The following yield components were evaluated: plant height and height of first-ear insertion; final plant population; ear length and diameter; number of rows per ear, number of grains per row and number of grains per ear; weight of 100 grains and yield. It can be concluded that all succession systems are agronomically viable for maize production in the ArenitoCaiua region, in conjunction with adequate crop nutrition management, especially the winter common vetch/summer maize succession system fertilized with poultry litter which produced the best maize yield.