Antagonistic effect of chitin-degrading microfungi on thick-shelled pig helminth eggs

The rising demand for pigs produced in organic farming systems, which require access to outdoor areas and associated increased risk of gastrointestinal nematode infections, is creating growing interest in alternative control strategies. Also development of anthelminthic resistance due to extensive use of anthelmintics is a concern in intensive pig production. Use of chitin-degrading microfungi is one of the options. Extensive research has been conducted on biological control of plant pathogenic nematodes using such fungi, and some fungal species are commercially available for plant protection. In contrast, there are only limited laboratory studies conducted on eggs from nematodes which are animal parasites. The aim of present study is to investigate the antagonistic effect of chitin-degrading microfungi on thick-shelled pig helminth eggs (i.e. Ascaris suum and Trichuris suis) both in the laboratory as well as in the field. We have performed a pilot study of the ovicidal effect of Paecilomyces lilacinus alone and in combination with chitin supplement on A. suum eggs over 4 weeks in 2% water agar. Within 1 week more than 90% of the eggs were hatched in both cases within the Petri dish as compared to controls, indicating that the fungus is capable of degrading the chitin wall so the larvae are becoming free. Soon we will proceed for full-fledged study with 2 fungal species (P. lilacinus and Pochonia chlamydosporia) which were proven to have ovicidal activity against nematode eggs. This will be done in the laboratory using soil samples amended with A. suum eggs, under semi-natural (pasture plot) conditions and finally on heavily contaminated pastures

Testing of bio-rational and synthetic pesticides to manage cabbage aphid (Brevicoryne brassicae L.) in cabbage field at Rampur, Chitwan, Nepal

Cabbage aphid (Brevicoryne brassicae L.) is an important pest of cabbage which reduces the yield and quality of the cabbage head. Farmers haven been using chemical pesticides to manage them but unfortunately these practices are toxic for human health, biodiversity and the environment. The study was conducted to test the efficacy of different bio-rational insecticides along with the chemical insecticide. ‘Green Coronet’ cabbage variety was used and the field experiment was laid out in the experimental farm of Agriculture and Forestry University (AFU), Rampur, Chitwan during the winter season of 2014.  The Experiment was designed in randomized complete block design with having 7 treatments (bio-rational insecticides with chemical and control)  and 3 replications. Plot size was 5.76 m2 (2.4m×2.4m) and spacing of 1 m was maintained between each blocks and plots. Field experiment showed that the highest reduction of cabbage aphid was obtained in Dimethoate (30 EC) treated plot followed by Derisom treated plot. The highest yield of cabbage head was obtained in Dimethoate treated plots (66.47 mt/ha) which was significantly at par with the Derisom (58.79 mt/ ha) treated plots. The yield for other treated plots were 47.60 mt/ha for Margosom, 43.77 mt/ha for Verticillium, 41.63 mt/ ha for Cow urine, 36.77 mt/ ha for Spinosad and control (33.45 mt/ ha) in terms of cabbage head yield. And, at the same time, natural enemies’ population was significantly lower to Dimethoate treated plots compared to bio-rational insecticides. Thus, Derisom (Derris based botanical) might be the best viable alternative in eco-friendly management of cabbage aphid considering cabbage head yield and protection of natural enemies. It was also evident from the research that Margosom (Neem based botanical) was found beneficial not only to conserve natural enemies in the cabbage field but also to minimize cabbage aphid population

NYT ØKOLOGISK TILTAG OVERFOR PARASITTER: Mikrosvampe kan bruges til biologisk kontrol af parasittiske spolorm i økologiske æglæggere

Mikrosvampe kan dræbe æg af fjerkræets spolorm. Projektet er derfor i gang med at undersøge om naturlige jordsvampe kan bruges til at inaktivere æg på smittede marker og i strøelsesmateriale og dermed kontrollere infektioner med spolorm i økologiske æglæggende høns

NEW ORGANIC APPROACH TO PARASITES: Biological control of parasitic roundworms in organic laying hens using microfungi

Microfungi can kill chicken roundworm eggs. This project investigates the use of naturally occuring soil microfungi to clean up contaminated pastures and bedding material, thereby controlling roundworm infections in organic laying hens

Effect of disinfectants on viability of Ascaris suum and Ascaridia galli eggs

Ascaris suum and Ascaridia galli, the large round worm of pigs and poultry, respectively, persist even in intensive management systems, where a high level of hygiene is practiced. It is necessary to control these helminths to minimize production losses and improve animal welfare. Commercial disinfectants are commonly used to clean pens in conventional pig and poultry farms but their efficacy against the thick-shelled nematode eggs has not been sufficiently documented. However, it might be difficult to control these parasites because of their complex thick-shelled eggs, which can resist harsh environmental conditions. Commonly used disinfectants such as Virkon S®, FL-des GA® typically claim efficacy against viruses, bacteria and some fungi, but very few disinfectants (FL-des Allround®) claim to also eliminate parasite eggs

Effects of different mulches and net house on crucifer aphid (Brevicoryne brassicae L.) population, growth and yield of broadleaf mustard (Brassica juncea)

Crucifer aphid, Brevicoryne brassicae, is a key pest of broadleaf mustard and other crucifers. An alternative integrated management approaches are recommended to keep the pest below economic threshold level. A field experiment was carried out to evaluate the effect of mulching and net house on aphid population, growth and yield of broadleaf mustard. Experiment was carried out in randomized complete block design with four replications from September to December 2016 at Rampur, Chitwan, Nepal. Five treatments used in experiment was untreated control, black plastic mulch only, reflective plastic mulch only, black plastic mulch plus imidacloprid 70 WSG @ 0.13gm/liter, and net house plus black plastic mulch. The results showed that the lowest population of crucifer aphid was recorded inside the net house with black plastic mulch and black plastic mulch with imidaclorpid 70 WSG @ 0.13g/L spray. Reflective plastic mulch was superior as compared to black plastic mulch and control to reduce the aphid population. Similarly, the highest yield (26.86t/ha) was obtained inside the net house with black plastic mulch followed by black plastic mulch with imidacloprid spray (25.99 t/ha). But the benefit-cost ratio was the highest (4.09) in black plastic mulch with imidacloprid spray followed by reflective plastic mulch (3.42), black plastic mulch (3.32), and net house with black plastic mulch (3.10). Benefit-cost ratio was lower in net house with black plastic mulch but products are safe from toxins and potentially profitable in long run. Considering its ecological cost, the use of pest exclusion net is recommended as a viable option for controlling insect pests of broadleaf mustard

Evaluation of soil microfungi as biological control agents against ascarid eggs

Thick-shelled ascarid eggs have been reported to remain infective in the environment for several years, thus posing a prolonged risk of infection to animals and/or humans. The following in vitro study was therefore conducted to evaluate the negative impact of two species of naturally occuring soil microfungi (Pochonia chlamydosporia and Paecilomyces lilacinus), on the viability of Ascaridia galli, Toxocara canis and Ascaris suum eggs. Approximately 150 fresh eggs of individual ascarid species were embryonated on a 2% water agar in Petri dishes with or without a fungus (P. chlamydospria or P. lilacinus). On days 7, 14, 21, 28, 35 and 42 post experimental set up (p.s.), the viability of the eggs in each experimental group was evaluated (destructive sampling). By day 14 p.s., P. chlamydosporia had reduced the viability of A. galli and T. canis eggs by 70-86% and 52-67%, respectively, compared to the controls. In contrast, P. lilacinus had reduced the viability of A. galli and T. canis eggs by only 17-30% and 6-28%, respectively. Neither fungal species was found to be effective against A. suum eggs (<4% reduction in both cases). These results indicate interspecies differences in the susceptibility of ascarid eggs to microfungi. Ascaridia galli and T. canis eggs seemed to have been degenerated mainly due to hydrolysis of shells by fungal enzymes. The present study demonstrates that P. chlamydosporia may potentially be utilized as a biological control agent against A. galli and T. canis eggs in the environment

Evaluation of soil microfungi as biological control agents against eggs of animal parasitic nematodes

Thick-shelled eggs of ascarid nematodes have been reported to remain infective in the environment for several years, thus posing a prolonged risk of infection to animal livestock and/or humans. An in vitro study was therefore conducted to evaluate the negative impact of two species of soil microfungi, Pochonia chlamydosporia and Purpureocillium lilacinum (syn. Paecilomyces lilacinus), on the viability of Ascaridia galli, Toxocara canis and Ascaris suum eggs. Approximately 150 fresh eggs of individual ascarid species were embryonated on a 2% water agar in Petri dishes with or without a fungus (P. chlamydospria or P. lilacinum). On days 7, 14, 21, 28, 35 and 42 post experimental set up (p.s.), the viability of the eggs from each experimental group was evaluated (destructive sampling). By day 14 p.s., P. chlamydosporia had reduced the viability of A. galli and T. canis eggs by 70-86% and 52-67%, respectively, compared to the controls. In contrast, P. lilacinum had reduced the viability of A. galli and T. canis eggs by only 17-30% and 6-28%, respectively. Neither fungal species was found to be effective against A. suum eggs (<4% reduction in both cases). These results indicate interspecies differences in the susceptibility of ascarid eggs to soil microfungi. Ascaridia galli and T. canis eggs seemed to have been degenerated mainly due to hydrolysis of shells by fungal enzymes. The present study demonstrates that P. chlamydosporia may potentially be utilized as a biological control agent against A. galli and T. canis egg contaminations in the soil environment

Evaluation of wheat (Triticum aestivum L.) genotypes for spot blotch (Bipolaris sorokiniana Sacc) resistance in terai condition of Nepal

Spot blotch caused by&nbsp;Bipolaris sorokiniana&nbsp;is a major disease of wheat in warm and humid regions of Nepal. The fungus has a worldwide distribution but as a pathogen, it is the most aggressive under the conditions of high relative humidity and temperature associated with the low fertility of soils in Nepal. The yield loss due to the disease is very significant in Nepal. This experiment was conducted to identify the genotypes having a good level of resistance against spot blotch. The experiment set was received from CIMMYT comprises 52 genotypes and arranged in alpha lattice design with two replications in 2017/18 at National Wheat Research Program, Bhairahawa, Nepal, and Regional Agricultural Research Station, Parwanipur, Bara, Nepal. Each plot size was 8 rows of 2 meters long. Three times disease scoring was done in the double-digit method and calculated the Area under the disease progress curve (AUDPC). Other data were analyzed by using R software (4.2.2). Heading days, days to maturity, plant height, number of grains per spike (NGPS), number of tillers per meter square (NTPM), mean AUDPC, thousand-grain weight (TGW), and grain yield were found highly significant. The genotype 8HLBSN47 was found the highest yielder (4996kg/ha) with a 304 mean AUDPC value. Seventeen genotypes (15.3%) found the lowest mean AUDPC, Penultimate leaf AUDPC, Flag leaf AUDPC, and the highest number of tillers per square meter, number of grains per spike, thousand-grain weight, and grain yield