Diversity and abundance of arbuscular fungi mycorrhizal (AMF) in rhizosphere Zea mays in tidal swamp

Sefrila M, Ghulamahdi M, Purwono Melati M, Mansur I. 2021. Diversity and abundance of arbuscular fungi mycorrhizal (AMF) in rhizosphere Zea mays in tidal swamp. Biodiversitas 22: 5071-5076. This study aims to find out the diversity and dominance of AMF spores and look at the morphology of fungi mycorrhizal arbuscular fungi that exist in the rooting area of corn (Zea mays L.) crops in the tidal swamp. The study was conducted in September 2020. Soil sampling at the tidal swamp village of Mulyasari Tanjung Lago District, Banyuasin, South Sumatra, Indonesia randomly sampling the corn root zone method. The research stages are soil sampling, soil chemistry analysis, AMF isolation and trapping, and morphological identification of AMF spores. The results showed the number of spores found in soil samples in the corn crop rhizosphere before trapping was less when compared to after trapping. The spores' shape is round, oblong, and oval, with colors ranging from clear, yellow, to brown. AMF spores found come from 2 genera namely (Acaulospora scrobiculata, A. bireticulata, A. mellea, A. laevis) and Glomus (Glomus monosporum, G. constrictum, G. manihotis).

Features of allelopathy between fusarium species and concomitant Trichoderma longibrachiatum in the maize rhizosphere in Kuban

The purpose of these studies was to study the interaction of pathogens of corn root rot in the agricultural sector of the Northern region of Krasnodar region. Corn root rot in the agricultural farms of the region annually cause significant damage to the harvest of silage and corn grain. In the course of research, the biological feature of the relationship between two species of the genus Fusarium: Fusarium concentricum Nirenberg & O'donnell and Fusarium proliferatum Matsush., optimizing the five-fold increase in the first species of mushroom compared to the growth of the second. PCR analysis revealed Fusarium oxysporum strain IMI 58289 with increased ability to exhibit elements of aggressive synergism. These fungi belong to the Department Ascomycota, order Hypocreales. In the soil of the studied rhizosphere, a natural hyperparasite – Trichoderma was detected, which can be used to minimize Fusarium infection.

First Report of Pythium torulosum Causing Corn Root Rot in Northeastern China

In October 2017, we collected five soil samples from each of several fields with a history of severe corn (Zea mays) seedling disease in Heilongjiang province of China. Affected seedlings were wilted with severe root rot, and a high incidence of seedling death was observed in the fields. Corn seeds were seeded in the collected soil samples and grown in a growth chamber for 21 days set at the following incubation temperatures: 21℃/7℃ for 6 days, 10℃/3℃ for 4 days, 16℃/7℃ for 5 days, 20℃/20℃ for 6 days (16 h/8 h, light/dark) (Tang et al. 2019). The corn seedlings in the growth chamber showed the same symptoms observed in the field as mentioned above. Corn root rot samples were collected from several symptomatic plants in the growth chamber to isolate the possible pathogen. Symptomatic roots were washed in 0.5% NaOCl for 2 min, rinsed in sterile water and cut into 1-2 mm segments and then plated on corn meal agar amended with pimaricin (5 μg/ml), ampicillin (250 μg/ml), rifampicin (10 μg/ml), pentachloronitrobenzene (50 μg/ml), and benomyl (10 μg/ml) (PARP+B), which is selective for oomycetes (Jeffers and Martin 1986). After 3 days of incubation in the dark at 25℃, colonies were transferred to 10% V8 juice agar and incubated at 25℃ for 2 weeks. Six isolates were identified as Pythium torulosum based on the morphology of sexual and asexual structures following van der Plaats-Niterink’s key (van der Plaats-Niterink 1981). On 10% V8 juice agar, the hypha were aseptate and colonies had filamentous sporangia with a dendroid or globose structure. The oogonia were globose or subglobose, laevis, terminal, rarely intercalary, ranging from 12-19 (average 16) μm. Antheridia were mostly sessile or brachypodous, and each oogonium was supplied by 1-2 antheridia cells. Oospores were globose, plerotic, ranging from 9-16 (average 13) μm. For the molecular identification, two molecular targets, the internal transcribed spacer (ITS) region of ribosomal DNA and cytochrome c oxidase subunit II (CoII), were amplified and sequenced using universal primer sets DC6/ITS4 (Cooke et al. 2000) and FM58/FM66 (Villa et al. 2006), respectively for one isolate, “copt”. BLAST analyses of a 971 bp ITS segment amplified from copt (GenBank Accession No. MT830918) showed 99.79% identity with a P. torulosum isolate (GenBank Accession No. AY598624.2). For the COⅡ gene of copt, BLAST analyses of a 553 bp segment (GenBank Accession MT843570) showed 98.37% identity with P. torulosum isolate (GenBank Accession No. AB095065.1). Thus, the isolate, copt, was identified as P. torulosum based on morphological characteristics and molecular analysis. To confirm pathogenicity and Koch’s postulates, a pathogenicity test was conducted as described by Zhang et al. (2000). Briefly, a 5 mm culture plug from the P. torulosum isolate, copt, was transferred to a 9-cm petri dish containing 20mL 10% V8 juice agar and incubated in the dark at 25℃ for 7 days. The culture was cut into small pieces and mixed with a sterilized soil mix (40% organic peat substrate, 40% perlite, and 20% soil) at a ratio of one petri dish per 100 g soil mix. Ten corn seeds were planted at a depth of 2 cm in a 500-mL pot containing the inoculated soil mix. The control pots were mock inoculated with plain 10% V8 juice agar. Pots were incubated in a greenhouse at temperatures ranging from 21 to 23℃. There were four replications. After 14 days, corn roots brown and rotted were observed, which was similar to those observed in the field and growth chamber. Control plants remained symptomless and healthy. P. torulosum copt was consistently re-isolated from the symptomatic roots. To our knowledge, this is the first report of P. torulosum causing root rot of corn in Northeastern China. Corn is an important crop in Heilongjiang and the occurrence of root rot caused by this pathogen may be a new threat to corn plants. There is a need to develop management measures to control the disease.

Lepidopteran Pests: Family Crambidae (Formerly Pyralidae), Subfamily Crambinae

This chapter addresses sod webworms, which refers to a large number of grass-infesting moths and larvae of the family Crambidae (formerly Pyralidae), subfamily Crambinae. Adults are often called lawn moths because of their habitat or snout moths because of the prominent labial palpi that extend in front of the head. Most of the turfgrass-infesting species originally were placed in the genus Crambus, which is distributed practically worldwide. About 100 species are recognized in North America. The six most important sod webworm species in the eastern temperate regions of the United States include the bluegrass webworm; the striped sod webworm; the silver-striped webworm; the larger sod webworm; the corn root webworm; and the subterranean webworm, also known as the cranberry girdler. Sod webworms restrict their feeding, with rare exceptions, to plants of the family Gramineae, and turfgrasses serve as ideal host plants. The chapter then considers tropical-region sod webworms.

Effect of Plant Residues-Treated Urea on Growth and N-Uptake of Wheat (Triticum aestivum L.)

A pot experiment was carried out to study the effect of the urea fertilizer treated with corn or conocarpus residues on growth and N uptake of wheat plant. Three kilograms of dry soil (Silt clay loam) were placed in a plastic pots and four levels of nitrogen (0, 60, 120 and 180 kg N ha -1) were added as urea. Urea was treated with one of the following methods : mix with the conocarpus leaves powder at rate of 4% of dry soil weight, mix with the conocarpus roots powder at rate of 4% of dry soil weight dissolved in, aqueous extract of the corn root at rate of 1/4 of the field capacity ,or coated with dried aqueos extract of corn root at ratio of 10% of urea weight. Treatment included urea treated with the standard chemical inhibitor (PMA) was used. shoot dry weight, N conc., N-uptake and N recovery were obtained. The results showed that treatment of urea fertilizer with water extract or coated with corn root extract resulted in improved growth parameters as compared with a PMA and control treatments .However ,treating urea with leaves or root powders decreased plant growth parameters .Urea coated with 10 % dried extract of corn roots gave the highest dry matter of 3.06 g pot-1 and nitrogen uptake of 69.90 mg pot-1 resulting in saving of 60 kg N ha-1 to give the same results for control and PMA treatments.

Development of an improved and accessible diet for western corn rootworm larvae using response surface modeling

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is an important pest of maize (Zea mays L.). Published WCR diets contain corn root powder, which is not available for purchase, thereby limiting the practical use of diets containing this ingredient. We applied response surface modeling combined with mixture designs to formulate a WCR diet that does not require corn root powder. We developed the new formulation by systematically exploring eight protein ingredients from animal, plant, and yeast sources based on simultaneous evaluation of three life history parameters (weight, molting, and survival). This formulation (WCRMO-2) without corn root powder supported approximately 97% of larval survival and successful molting. Larval weight gain after 10 days of feeding on WCRMO-2 was 4-fold greater than that of larvae feeding on the current best published WCR diet. Additionally, there was no significant difference in these larval performance traits when larvae were reared on WCRMO-2 and the best proprietary WCR diet. A commercial version of WCRMO-2 was tested and found to perform comparably for these traits. These improvements met our goal of a diet comprised of available ingredients that supports performance of WCR larvae equal to or better than publicly available formulations and proprietary formulations.