Chalky spot damage caused by stink bugs on red lentil seeds in Southeast Anatolia Region, Turkey

Chalky spot damage on red lentil is the most important problem waiting for a solution regarding plant health at lentil cultivation in Southeast Anatolia Region, Turkey. The stink bugs, Piezedorus lituratus (F.) and Dolycorus baccarum L. were subjected to trials in cages and in sprayed and unsprayed plot trials in open lentil fields and fields containing windrowed lentils after harvesting. The study revealed that P. lituratus and D. baccarum feeding on red lentil caused chalky spot damage. Average damage to lentil seeds caused by P. lituratus was 13% and 7.8% and by D. baccarum was 4.9% and 2% in 2010 and 2011, respectively. There was a positive relation between P. lituratus density and chalky spot damage (r =0.788, r2 =0.621, P=0.000). The study also showed that after the harvesting, the stink bugs gathered under windrowed lentils and continued feeding and causing chalky spot damage. The damage in unsprayed windrowed lentils (6.60%) was approximately 12-fold higher than that in sprayed windrowed lentils (0.57%). Study suggests conduction of future work on environmental friendly control methods of stink bugs and alternative harvesting methods.

Evaluation of Plant Extracts against Stemphylium Blight of Lentil

Experiments were carried out to evaluate five different plant extracts against lentil stemphylium blight (Stemphylium botryosum Walr.) at the Grain Legume Research Program, Rampur, Chitwan, Nepal during two winter seasons (2011/ 12 and 2012/13) using CRD in laboratory and RCBD in field conditions. Water extract of Acorus calamus at higher dose (8% W/V) was able to check the growth of the pathogen completely in-vitro. The mycelial growth inhibition (%) of Xanthoxylum armatum and Lantana camera at 8% concentration in PDA were 31.17 and 24.56 respectively. In the field experiment during 2011/12, extracts were sparingly effective for a short period. However the disease control (PDC) was higher in X. armatum treated plot (31.60%) followed by A. calamaus (28.69%) and L. camera (27.61%) when compared to unsprayed plot. The following year (2012/13) field experimental results also verified the effect of plant extracts against the disease. The lower Disease (%) Index (PDI) was obtained from the plots treated with A. calamus (35.33%) and X. armatum (35.55%). Higher crop yield was recorded from the plot treated with A. calamus (987.39 kg/ha) followed by X. armatum (972.78 kg/ha). Two years’ experimental results revealed that A. calamus and X. armatum were effective botanicals to manage lentil Stemphylium blight.Nepal Journal of Science and Technology Vol. 16, No.1 (2015) pp. 11-16

Field Evaluation of Plant Extracts for the Control of Diamond Moth (Plutella xylostella Linnaeus) Infesting Cabbage (Brassica oleracea Linn)

Cabbage (Brassica oleracea Linn.) is one of the important vegetables grown worldwide. Insect pests have been a major constraint to its production with some reported to have developed resistance to commonly available synthetic insecticides. In order to find alternative control for these pests, field experiments were conducted in the early seasons of 2011 and 2012, to evaluate the efficacy of three plant extracts, Tephrosia vogelli Hooks, Zingiber officinales Rosh and Lantana camara Spanish flag, applied at 5, 10 and 25 % w/v concentrations Delthamethrin (a synthethic insecticide) and an unsprayed plot were included as positive and negative controls respectively. Plots were arranged in a Randomized Complete Block Design (RCBD), with three replications. Mean Data over the two planting seasons were subjected to the analysis of variance and significant means were compared using the least significant difference (L.S.D) at P < 0.05. Z. officinales extract effectively control P. xylostella larvae at all concentrations with 25 % w/v gave the best yield of 0.50 kg/ha while T. vogelii and L. camara extracts were as effective as Deltamethrin at different concentrations and hours on diamondback-moth (P. xylostella) adult The present findings indicated that effective botanicals against Diamondback moth adult and larvae of cabbage can be formulated from extract of T. vogelii, L. camara and Z. officinales at 25 % concentration respectively.

Efficacy and Economics of Management Strategies to Control Anthracnose Fruit Rot in Processing Tomatoes in the Midwest

Anthracnose (Colletotrichum coccodes) is the major fungal disease affecting processing tomato fruit in the midwestern United States. Currently available disease management strategies evaluated for controlling anthracnose fruit rot (AFR) on processing tomatoes include genetic resistance and the fungicide chlorothalonil applied according to conventional schedules or a disease-forecasting system (Tom-Cast). Experimental field plots were established in West Lafayette, Indiana, and East Lansing, Michigan, in 1993 to 1995. Chlorothalonil was applied every 7, 10, or 14 days or according to Tom-Cast with a threshold of 20 disease severity values, and was not applied to the control. In Michigan, Phytophthora infestans (1993) and C. coccodes (1993 to 1994) caused 91.8% (1993) and 30.7% (1994) fruit rot in the unsprayed plot. In Indiana, C. coccodes caused 69.8% (1993) and 39.0% (1994) AFR in the unsprayed plot. In 1995, Ohio 8245 (Michigan and Indiana), considered to be less prone to anthracnose, and Ohio 7814 were integrated into the conventional and Tom-Cast—prompted spray programs. Cultivar did not affect the incidence of AFR or foliar blight caused by Septoria lycopersici and Alternaria solani in either location. In 1993 and 1994, chlorothalonil applied at 10-day intervals in Indiana resulted in the highest benefit per hectare (BPH) and return per fungicide dollar (RPFD). In 1995, the highest BPH and RPFD resulted from chlorothalonil applied every 14 days to Ohio 8245 (Michigan). Chlorothalonil applied according to the Tom-Cast program resulted in a level of AFR that was generally not statistically different from the 7-day treatment but was high enough to result in crop rejection and high economic loss in 2 of the 3 years the study was conducted. Based on data from this study, it is not commercially feasible to grow processing tomatoes in Michigan and Indiana without chlorothalonil to protect against AFR even when a resistant cultivar is used.

Validation of 'Downcast' in the prediction of sporulation-infection periods of Peronospora destructor in the Lockyer Valley.

The disease forecasting system 'Downcast' was developed in Canada to indicate sporulation-infection periods of Peronospora destructor (Berk.) Caspary in onions. During 1989, observations were made of downy mildew development in trap plants and of disease progress in an unsprayed plot of onions in the Lockyer Valley, Queensland, and related back to predicted sporulation-infection periods using the forecaster. Over 113 days, there were 20 days when sporulation and infection were predicted, and of these 14 occurred during 4 weeks in July and August. Of 16 groups of trap plants exposed in the field, each for 7 days, 7 were subjected to predicted sporulation-infection periods. Two predicted sporulation-infection periods early in the season did not result in infection of trap plants or of plants in the field plot, probably due to absence of inoculum. Subsequently, groups of trap plants exposed in the field during predicted sporulation-infection periods became infected while those exposed when weather was unsuitable remained healthy. 'Downcast' shows promise as a technique for more effective management of disease caused by Peronospora destructor.

POPULATION GROWTH OF THE PEA APHID, ACYRTHOSIPHON PISUM (HARRIS) (HOMOPTERA: APHIDIDAE), AND PLANT RESPONSE TO APHID NUMBERS IN COMMERCIALLY GROWN FIELD PEAS IN MANITOBA

Pea aphids, Acyrthosiphon pisum (Harris), were sampled weekly or biweekly over the summers of 1985 and 1986 in a total of 15 commercial plantings of Century, Trapper, or Triumph field peas across Manitoba. Pea aphid populations rose more quickly in fields of Trapper than in Century or Triumph fields. The owners of all Trapper fields sampled initiated aerial application of insecticide for pea aphid control; at the time of spraying in 1985, plants in Trapper fields had significantly greater numbers of aphids in sweep samples than such samples from Century or Triumph fields. In 1986, Triumph plants supported greater numbers of aphids than Century or Trapper plants. Triumph plants remained green longer than plants of the other cultivais; in 1985 pea aphid numbers on this cultivar were highest on the last date sampled.Yield components were measured in sprayed and unsprayed plots within the commercial fields. When data were averaged for each cultivar, there were no significant differences in yield per area or in 1000 seed weight between sprayed and unsprayed plots. Data indicated that existing economic thresholds are too low for Trapper peas. However, one of the fields of Trapper peas that we sampled had significantly reduced numbers of pods per plant, yield per square metre, and weight of 1000 seeds in the unsprayed plot; this field had the largest population of pea aphids of any field sampled, with aphid numbers peaking at 48.5 ± 9.2 (SE) per plant lip during pod formation and filling. Significant yield losses also occurred in unsprayed plots of a Triumph field, which had a peak aphid population of 4.8 ± 1.6 per plant stem at pod maturation.