Open Access Original Research Article

Functional Response of Two Egg Parasitoids of Trichogramma (Hymenoptera: Trichogrammatidae) Genre on Duponchelia fovealis Zeller (Lepidoptera: Crambidae) Eggs

João Paulo Pereira Paes, Victor Luiz Souza Lima, José Romário de Carvalho, Dirceu pratissoli

Journal of Experimental Agriculture International, Page 1-7
DOI: 10.9734/JEAI/2018/39795

Aims: To evaluate the potential of the parasitoids of the genus Trichogramma on European pepper moth, a functional response bioassay was performed with two Trichogramma lineages and different egg densities of the host.

Study Design: Adopting a completely randomized experimental design, 10 replications were done for each species.

Place and Duration of Study: The bioassay was conducted at the Entomology Laboratory of the Universidade Federal do Espírito Santo (CCAE-UFES) in Alegre, ES, Brazil, in the year 2017.

Methodology: The functional response bioassay was done for the T. pretiosum and T. galloi for the different D. fovealis egg densities (5, 10, 15, 20, 25 and 30 eggs). After the host eggs were glued to a paperboard, it was inserted into a flat bottom glass tube. Next, a parasitoid female was introduced into each tube. The tubes which were sealed with PVC plastic film were then placed in air-conditioned chambers keeping adjusted at 25°C temp., RH at 70 ± 10 % and a photoperiod of 14 h. Then 24 h later, the parasitoid was removed from the tube and the paperboard with the parasitized eggs was left in the tube until the offspring emerged.

Results: For both the Trichogramma species, the functional response was confirmed to be type II, with the Rogers model being the most fitting. An interaction between the factors of parasitoid species and host density (F5,102 = 2.756, P = 0.022) was observed. The search efficiency for T. pretiosum and T. galloi were determined as 0.1799 ± 0.025 and 0.0976 ± 0.011 h-1, while the handling time was assessed as 0.9852 ± 0.077 and 0.5751 ± 0.101 h, respectively.

Conclusion: The estimated values for the parameters search efficiency and handling time revealed that T. pretiosum and T. galloi are potential candidates for the biological control of D. fovealis.

Open Access Original Research Article

Feeding Preferences and Digestive Physiology of Indian Carps in Polyculture Pond System

Gajender Singh, Anita Bhatnagar, Kalla Alok, Singh Ashneel Ajay

Journal of Experimental Agriculture International, Page 1-10
DOI: 10.9734/JEAI/2018/39077

Catla (Catla catla), mrigala (Cirrhinus mrigala) and rohu (Labeo rohita) are commercially significant pond species in India. Despite being cultured for a long time in village ponds, sufficient information on the feeding preference and digestive physiology variables of these species in managed and unmanaged polyculture pond systems in India is not available. We carried out the gut content analysis and estimated the forage ratio for catla, rohu and mrigala species. The intestinal enzymes and liver glycogen were also estimated. Analysis of gut contents of C. catla indicated that the fish is herbivorous or phytoplanktivorous. Gut contents of L. rohita from all the ponds indicated it is Omniplanktivorus fish. In case of C. mrigala, the gut contents indicated that the fish is zooplanktivorous. Based on the results of digestive physiology, it can be inferred that consumable plant material would probably be exploited with the highest intensity by C. catla compared to L.rohita and with the lowest intensity by C. mrigala. On the other hand, animal components would be utilized more intensively by C. mrigala followed by L. rohita and with least intensity by C. catla. Digestive enzyme activity appeared to be comparatively higher in managed ponds. This study provides a deeper insight on the occupation of different feeding stratus by the three species of fish within the available food in polyculture arrangement allowing better understanding of how good production occurs and revealing that each species is focusing on a particular feeding stratus.

 

Open Access Original Research Article

Effect of Plant Growth Regulators and Packaging on Flowering, Fruit Quality and Shelf Life in Mango cv. Amrapali

Shurhozenuo Naleo, Akali Sema, C. S. Maiti

Journal of Experimental Agriculture International, Page 1-8
DOI: 10.9734/JEAI/2018/38059

Aims: To study the influence of plant growth regulators on flowering, yield, shelf life and its combined effect with packaging on quality and shelf life.

Study Design:  Factorial Randomized Block Design

Place and Duration of Study: Horticulture Experimental Farm, School of Agricultural Sciences and Rural Development, Medziphema Campus, Nagaland University, Medziphema during 2006-2008.

Methodology: Pre-harvest treatments comprised of foliar spray of growth regulator naphthalene acetic acid (NAA) @ 100ppm and soil drenching Paclobutrazol (PBZ) @ 5ml/L/tree along the drip zone prior to bud differentiation in the month of September and a control (no treatment) on the mango tree. Fruits of uniform size without injury or decay were harvested from tagged trees and transported immediately to laboratory for the post-harvest experiments (polyethylene packing and control).

Results: PBZ treatment greatly influenced flowering, yield and fruit quality attributes and induced early flowering (79 days), higher flowering shoots (85.77 %), number of fruitlets per panicle (5.56), number of fruits per panicle at harvesting stage (2.23), number of fruits per tree (44.52) and fruit yield (8.62 kg per tree). TSS (11.93oBrix), TSS: Acid ratio (16.54), total sugar (8.43 %) and ascorbic acid content (47.03 mg/100g pulp) of mango fruit were also influenced by PBZ treatment. In contrast, NAA treatment showed higher fruit weight, fruit size, pulp weight and pulp: stone ratio. The post-harvest treatments consist of packing the fruits with polyethylene material of 0.3 mm thickness and 32 x 25 cm size and control. The pre- and post-harvest treatments had significant influence on the physiological loss in weight (PLW), appearance, sensory quality, firmness, total sugar, reducing sugar and non-reducing sugar of the fruit during storage. Shelf life was significantly influenced by pre- and post-harvest treatments. Shelf life was recorded more in PBZ treatment (15.33 days) closely followed by NAA treatment (15 days) where the influence reached the level of significance. Further analysis revealed that fruits from polyethylene packing showed the significantly better result with 14.89 days of shelf life as compared to control with only 13.33 days.

Conclusion: Both PBZ @ 5 ml and NAA @ 100 ppm are effective as pre-harvest treatment for enhancing the floral characters, yield and its attributes as well as physicochemical characteristics of fruits. Polyethylene packed fruits had lower PLW, better appearance and firmness, higher ascorbic acid and shelf life.

Open Access Original Research Article

Ultraviolet-C Radiation on Psidium cattleyanum L. Conservation and Its Influence on Physico-chemical Fruits Characteristics

T. F. Acosta, L. O. Marques, I. C. Nardello, R. Navroski, P. C. Mello-Farias

Journal of Experimental Agriculture International, Page 1-7
DOI: 10.9734/JEAI/2018/38521

Aims: The present study aimed to evaluate UV-C radiation influence on physicochemical and phytochemical characteristics of yellow cherry guava fruits.

Study Design: The staining data obtained were submitted to analysis of variance (ANOVA), being the results compared with each other by the test of Tukey (P = .05). The other data were submitted to the ANOVA (P = .05), and when there was a significant difference, the means were compared by the Hartley Test (P = .05).

Place and Duration of Study: The study was developed in March 2017 at Palma Agricultural Center and Post-Harvest and Fruit Quality Laboratory at LabAagro, at Federal University of Pelotas (UFPel).

Methodology: Psidium cattleyanum fruits near the maturity point were harvested in the orchard. The fruits were divided into a completely randomized design, with four treatments, which had four replicates composed of fifteen samples each. Evaluations and UV-C radiation were performed at intervals of four days from zero to 12 d, being two minutes the exposure time of the fruits to UV-C radiation in each application, fruits were stored in a cold chamber at 4°C temperature and relative humidity of 85-90%. The variables analyzed were skin colour, fruit length, fruit diameter, soluble solids (SS), initial fruit weight, final fruit weight, mass loss, hydrogen ionic potential (pH) and titratable total acidity.

Results: UV-C radiation usage did not significantly interfere with the physicochemical characteristics of the evaluated yellow cherry guava fruits.

Conclusion: The use of UV-C radiation associated with cold-chamber storage maintained fruit quality for a period significantly longer compared to storage at room temperature.

Open Access Original Research Article

Effects of Biochar, Rice Husk and Rice Straw on Productivity of Maize (Zea mays L.) and Sustainable Soil Fertility Restoration

Israel K. Dzomeku, Osman Illiasu, Isaac K. Amegbor

Journal of Experimental Agriculture International, Page 1-11
DOI: 10.9734/JEAI/2018/39346

Integrated soil fertility management technology fits into the status of resource poor farmers in the Guinea savannah zone of Ghana. A field experiment was conducted at Nyankpala during the 2014 cropping season, to investigate the effects of Biochar, Rice husk and Rice straw and subsequently the residual impact on yield components and grain yield of maize. The study was a 3×3×3 factorial experiment consisting of three organic materials at three levels (2.5, 5 and 7.5 t ha-1 on dry matter basis) and three NPK rates (0-0-0, 45-30-30 and 90-60-60 kg ha-1) laid out in a Randomized Complete Block Design with four replications. The highest grain yield was obtained with 7.5 t ha-1 biochar (4825 kg ha-1) plus at 90-60-60 kg NPK t ha-1, but 7.5 t ha-1 a biochar plus 45-30-30 kg NPK t ha-1 gave similar yield making the dose more acceptable. Longest cob was obtained with 5 to 7.5 t ha-1 of biochar (22.60 cm), or rice husk (20.69 cm), or rice straw (21.45 cm) plus at least 45-30-30 kg NPK ha-1. Shortest days to 50% flowering was found in 5 to 7.5 t ha-1 biochar (48.7), 5 to 7.5 t ha-1 rice husk (49.1) and 5 to 7.5 t ha-1 rice straw (49.6) plus at least 45-30-30 kg NPK ha-1 applications. Overall, organic materials supplemented with NPK fertilizer gave better results than sole organic materials or NPK fertilizer. The correlation coefficient of grain yield with stover weight and 100 seed weight were (r=0.757**) and 100 seed weight (r=0.678**) respectively. Organic materials plus at least 45-30-30 kg NPK ha-1 increased soil organic carbon content (72.8%), Nitrogen (95.6%), Phosphorus (54.6%) and Potassium (17.2%) for maize production.