A double-stranded RNA (dsRNA) of approximately 16 kbp was isolated from symptomless common buckwheat (
Fagopyrum esculentum
) plants. The size of the dsRNA suggested that it was the replicative form ...of an endornavirus. The dsRNA was sequenced, and it consisted of 15,677 nt, containing a single open reading frame that potentially encoded a polyprotein of 5190 aa. The polyprotein contained conserved domains for a viral methyltransferase, viral RNA helicase 1, MSCRAMM family adhesion SdrC, UDP-glycosyltransferase, and viral RNA-dependent RNA polymerase 2. A site-specific nick in the plus strand was detected near the 5' end of the dsRNA. BLASTp analysis showed that the polyprotein shared the highest identity with the polyprotein of winged bean endornavirus 1. Results of phylogenetic analysis supported placing this novel virus from common buckwheat, which was provisionally named "Fagopyrum esculentum endornavirus 1", in the genus
Alphaendornavirus
of the family
Endornaviridae.
Two new fungicides, flutianil and pyriofenone were introduced into the Japanese market in 2013 and 2014, to control powdery mildew on cucumber. Isolates of
Podosphaera xanthii
, the causal agent of ...powdery mildew, were collected in Ibaraki Prefecture, Japan, between 2017 and 2019 from cucumber greenhouses with a history of flutianil and pyriofenone usage. They were then tested for sensitivity to both fungicides by the leaf disc test. First, the sensitivity of three baseline reference isolates to each fungicide was determined. Minimum inhibitory concentrations values were 0.0063 μg/ml for flutianil and 10 μg/ml for pyriofenone, while 50% effective concentration (EC
50
) values of these fungicides were 0.00013–0.00035 μg/ml and 0.39–0.70 μg/ml, respectively. To determine the current sensitivity of
P. xanthii
in detail, 23 single-spore isolates were then sampled from five greenhouses and tested. Nineteen isolates showed high resistance (Flu-HR/Pyr-HR) with EC
50
values of >100 μg/ml for flutianil and > 1000 μg/ml for pyriofenone. The low sensitivity of Flu-HR/Pyr-HR isolates was stable even after 46 subcultures on fungicide-untreated cotyledons. Additionally, two isolates showed moderate resistance (Flu-MR/Pyr-MR) to flutianil (EC
50
: mean 0.8 μg/ml) and pyriofenone (mean 58.7 μg/ml). The results from foliar inoculation tests on potted cucumber plants confirmed low efficacies of flutianil and pyriofenone against resistant isolates. Among a total of 122 isolates sampled from 13 greenhouses, 89 isolates (73.0%) were categorized as Flu-HR/Pyr-HR and two isolates (1.6%) as Flu-MR/Pyr-MR. This is the first report on flutianil resistance in any pathogen.
Natural predators such as
are known for their role in managing greenhouse pests. However, techniques in maximizing the biological control potential of
under field conditions are still lacking. We ...evaluated under greenhouse conditions the prospects of
cysts enhanced with high fructose corn syrup and honey, and delivered using hemp strings (hemp rope) as supplementary factitious dietary in augmenting the proliferation and spread of
on tomato plants. Results showed that
supplemented with hemp rope could establish, proliferate and disperse among tomato plants compared to the
supplemented with banker plants. Even though
proliferated exponentially on banker plants, their movement and relocation to tomato plants, as expected, were only congested on tomato plants near the banker plants. However, as the survey continued, they relocated to the rest of the tomato plants. Furthermore, the number of
eggs and nymphs, a serious greenhouse pest of tomato, was observed to be significantly reduced in hemp rope greenhouse compared to banker plants and the negative control (no pest control system) greenhouses. This study, therefore, establishes foundational data on the usage of
cysts enhanced with isomerized sugar (high fructose corn syrup) and honey under greenhouse conditions as factitious supplementary dietary in supporting
establishment and spread, traits that are essential towards development of whitefly Integrated Pest Management (IPM) system. enhanced with isomerized sugar (high fructose corn syrup) and honey.
Nesidiocoris tenuis is a zoophytophagous mirid bug widely studied for its role in preying on major greenhouse pests. Since N. tenuis has now been known for its vigorous predation potential on pests ...such as Bemisia tabaci, many applied entomologists are now recommending that N. tenuis be merged into the Integrated Pest management (IPM) systems. However, successful integration of N. tenuis into any IPM system depends on thorough evaluation with compatible pesticides, as incompatible pesticides can offset the whole idea of IPM. Here, we simulate the field situation where N. tenuis feeds directly on a contaminated B. tabaci nymph or leaves. However, instead of using live B. tabaci nymphs, we used brine shrimp eggs, Artemia salina (Linnaeus, 1758). Brine shrimp eggs have been reported to be an excellent factitious supplementary diet in augmenting N. tenuis populations. Thus, we use brine shrimp eggs to determine the toxicity of pesticides, to which the calculated mortality rates can be used to determine which pesticides can be used together with N. tenuis in an IPM system against any related pest.•We developed a customized containment system that promotes aeration and minimize contamination.•Pesticide contaminated hatched brine shrimp eggs is delivered to N. tenuis in the aerated containment system.•In addition to established methods such as leaf dipping or insect dipping, this method shows to mimic N. tenuis feeding on contaminated B. tabaci nymphs in field conditions thus, predicts how a pesticide may be of toxic or compatible with N. tenuis when both are integrated together.
Schematic representation of the customized containment tube housing the Nesidiocoris tenuis with contaminated brine shrimp eggs. Display omitted
Two soil-borne fungal endophytes almost completely suppressed the effects of a post-inoculated and virulent strain of Fusarium oxysporum f. sp. melonis when inoculated to axenically reared melon ...seedlings in Petri dishes. They were identified as Cadophora sp. on the basis of ITS 1–5.8S rDNA–ITS 2 sequences and morphological characters and obtained from the roots of Chinese cabbage grown as bait plants in a mixed soil made up of samples from different forest soils from Alberta and British Columbia, Canada. Hyphae of Cadophora sp. grew along the surface of the root and colonized root cells of the cortex and reduced the ingress of the Fusarium pathogen into adjacent cells. Melon seedlings pre-inoculated with Cadophora sp. were also grown in soil amended with the different N sources, nitrate or the amino acids leucine and valine, and glucose (final C:N ratio = 10:1). After 4 weeks, these seedlings were transplanted into the field and disease symptoms were assessed. Only the endophyte-inoculated seedlings treated with valine could effectively inhibit the development of Fusarium wilt in two plots and reduced disease symptom development by 43 and 62 %.
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