Meloidogyne chitwoodi
Golden, O’Bannon, Santo & Finley, 1980 and
M. hapla
Chitwood, 1949 are important pests of potato in Turkey. This study was conducted in three experimental areas where ...conventional agronomic practices have been done in Niğde (Center district) and Nevşehir (Center and Derinkuyu districts) provinces. Nematodes were extracted by modified Oostenbrink dish from soil samples taken from 0 to 30 cm depths every month between 2014 and 2017 to assess the population fluctuations of these root-knot nematodes under field conditions. The whole suspension was checked for
Meloidogyne
juveniles which were counted under an inverted microscope. Morphological and molecular identification results showed that two experimental areas were infested by
M. chitwoodi
while one experimental area (Derinkuyu) was infested with both
M. chitwoodi
and
M. hapla
. Our study showed that
M. chitwoodi
population level decreased during wheat cultivation and were maintained under rye cultivation, whereas
M. chitwoodi
and
M. hapla
population levels increased rapidly under potato and bean cultivation. It was found that
M. chitwoodi
population increased more when potatoes were planted, while
M. hapla
increased more in bean. The best sampling time for
M. chitwoodi
and
M. hapla
was observed to be right after harvest, when the population was highest, but both could be detected in soil samples even when the ambient temperature was below zero. These results demonstrated that farmers should be careful in their choice of rotational crop with potatoes in areas infested with
M. chitwoodi
and
M. hapla
.
Fusarium crown rot, caused by several species within the genus, is a major constraint that results in significant losses in wheat production worldwide. In June 2019, diseased wheat plants with ...typical symptoms of crown rot, including discoloration on the first two or three internodes of the stem just above the soil line and stunted, dry rotted, and discolored roots were collected in several bread wheat fields during the maturity stage in Almaty, East Kazakhstan, and Karaganda Regions of Kazakhstan. For each field, approximately twenty tillers were randomly sampled. Symptomatic tissues were surface sterilized in 1% NaClO for 2 min, rinsed with sterile distilled water three times, air-dried in a laminar flow hood, and then transferred to Petri dishes containing one-fifth strength potato dextrose agar (PDA). After incubating in the dark at 23°C for 5 days, 79 single-spore isolates showing cultural and microscopic characteristics of Fusarium were obtained on PDA and Spezieller-Nährstoffarmer agar (SNA). Colonies were initially white but later produced a beige to pink diffusible pigment in PDA. Microconidia that formed on aerial monophialides were hyaline, 0 to 1 septum, oval- to kidney-shaped, and measured 4.3 to 10.3 × 1.9 to 3.4 µm (average 7.8 × 2.6 µm), whilst macroconidia were straight to slightly curved, 3 to 5 septate, and measured 18.7 to 38.8 × 2.9 to 6.6 µm (average 29.9 × 4.7 µm), with foot-shaped basal cells on SNA. Chlamydospores were present on PDA. Sequence analysis based on portions of translation elongation factor 1α (TEF1) and the nuclear ribosomal internal transcribed spacer region (ITS rDNA) loci with primers EF1/EF2 (O'Donnell et al. 1998) and ITS1/ITS4 (White et al. 1990) identified 29 of the 79 isolates as Fusarium redolens Wollenw. The sequences of the five representative isolates with 99.85% of similarity to those of F. redolens strains available in GenBank e.g., ITS (MT435063) and TEF1 (GU250584). The TEF1 (accession nos. MW403914-MW403918) and ITS rDNA (accession nos. MW397138-MW397142) sequences of the isolates were deposited in GenBank. The morphological features are consistent with the described features of F. redolens (Leslie and Summerell 2006). To confirm pathogenicity of the five isolates, five pre-germinated seeds of wheat cultivar Seri 82 were placed in a 9-cm-diameter pot filled with a sterile potting mix containing equal volumes of peat, vermiculite, and soil. An approximately 1-cm-diameter 7-day-old mycelial plug of each isolate was individually placed in contact with the seeds. Seeds were covered with the same potting mix, and then the pots were maintained for four weeks in a growth chamber at 23°C with a 12-h photoperiod. The experiment was conducted twice with three replicate 15-cm pots with 5 plants per pot. Controls were inoculated with sterile agar plugs using the same procedure. After four weeks, all the inoculated plants showed stunted growth with brown discoloration in most parts of the crown and roots, whereas no symptoms were observed in the control plants. The mean severity of the disease for each isolate was between 2.1 and 2.7 according to the scale of 1 to 5 described by Gebremariam et al. (2015). The pathogen was reisolated from crowns of diseased plants, but not from asymptomatic control tissues, and identified morphologically based on the methods described above, fulfilling Koch's postulates. Although several morphological features are shared by F. oxysporum and F. redolens, Baayen et al. (2001) showed that these species could be easily distinguished using molecular data. The pathogen was previously reported as F. redolens associated with crown rot of wheat in Turkey (Gebremariam et al. 2015) and Saskatchewan, Canada (Taheri et al. 2011). The presence of F. redolens causing crown rot is confirmed in the six wheat fields surveyed in Kazakhstan, for the first time. This pathogen may pose a risk for wheat production, and further studies needed to determine the impact on the crop in Kazakhstan.
Vector-borne diseases pose a severe threat to human and animal health. Culex pipiens L. (Diptera: Culicidae) is a widespread mosquito species and serves as a vector for the transmission of infectious ...diseases such as West Nile disease and Lymphatic Filariasis. Synthetic insecticides have been the prime control method for many years to suppress Cx. pipiens populations. However, recently, the use of insecticides has begun to be questioned due to the detrimental impact on human health and the natural environment. Therefore, many authorities urge the development of eco-friendly control methods that are nontoxic to humans. The bacterial associates Xenorhabdus and Photorhabdus spp. (Enterobacterales: Morganellaceae) of entomopathogenic nematodes (EPNs) (Sterinernema spp. and Heterorhabditis spp.) (Rhabditida: Heterorhabditidae and Steinernematidae) are one of the green approaches to combat a variety of insect pests. In the present study, the mosquitocidal activity of the cell-free supernatants and cell suspension (4 × 107 cells mL−1) of four different symbiotic bacteria (Xenorhabdus nematophila, X. bovienii, X. budapestensis, and P. luminescens subsp. kayaii) was assessed against different development stages of Cx. pipiens (The 1st/2nd and 3rd/4th instar larvae and pupa) under laboratory conditions. The bacterial symbionts were able to kill all the development stages with varying levels of mortality. The 1st/2nd instar larvae exhibited the highest susceptibility to the cell-free supernatants and cell suspensions of symbiotic bacteria and the efficacy of the cell-free supernatants and cell suspensions gradually declined with increasing phases of growth. The highest effectiveness was achieved by the X. bovienii KCS-4S strain inducing 95% mortality to the 1st/2nd instar larvae. The results indicate that tested bacterial symbionts have great potential as an eco-friendly alternative to insecticides.
The codling moth,
(L.) (Lepidoptera: Tortricidae), is one of the major pests in pome fruit production worldwide. Heavy treatment of the larvae of
with insecticides triggered the development of ...resistance to many groups of insecticides. In addition, the increasing concern about the adverse effects of synthetic insecticides on human health and the environment has led to the development of sustainable and eco-friendly control practices for
. The entomopathogenic nematodes (EPNs) (
and
spp.) and their endosymbionts (
and
spp.) represent a newly emerging approach to controlling a wide range of insect pests. In the present study, field surveys were conducted in apple orchards to isolate and identify EPNs and their endosymbionts and evaluate their insecticidal efficacy on the larvae of
. EPNs were isolated from 12 of 100 soil samples (12%). Seven samples were identified as
(Filipjev, 1934) (Rhabditida: Steinernematidae), whereas five samples were assigned to
(Poinar, 1976) (Rhabditida: Heterorhabditidae). The pathogenicity of the EPN species/isolates was screened on the last instar larvae of
. The two most pathogenic isolates from each EPN species were tested against fifth instar larvae of
under controlled conditions. The maximum mortality (100%) was achieved by all EPN species/isolates at a concentration of 100 IJs/larva 96 h after treatment. The endosymbionts of selected
and
species were identified as
subsp.
and
, respectively. The mortality rates ranged between 25 and 62% when the fifth larval instar larvae of
were exposed to the treatment of cell-free supernatants of symbiotic bacteria. In essence, the present survey indicated that EPNs and their symbiotic bacteria have good potential for biological control of
.
In this study, morphological and molecular characterizations of twenty-four
Heterodera
populations (cereal cyst nematodes, CCNs) collected from wheat production fields in Turkey were carried out. ...Light microscopy, species-specific markers, RFLP, and ITS sequencing were used to identify the nematode populations. The obtained CCN populations were identified as
Heterodera avenae
,
H. filipjevi
, and
H. latipons
according to the morphometric analysis, which was confirmed by the molecular techniques. The ITS region sequencing analysis confirmed the species identification, and phylogenetic analysis of this region grouped the populations with representative
Heterodera
populations from different origin countries deposited in GenBank. The simulation of four restriction enzymes,
Alu
l,
Pst
I,
BsuR
I (
Hae
III), and
Rsa
l, employed the ITS sequences of isolates to discriminate the Turkish
Heterodera
populations. ITS-RFLP patterns produced by endonuclease enzymes provided variations among
Heterodera
species. There was no intraspecific variation in populations of each
Heterodera
species in the ITS-RFLP analyses. The species-specific primers, AvenF-COI/AvenR-COI, HfF/HfR, and H-LatF/H-LatR, yielded 109 bp, 646 bp, and 204 bp products for
H. avenae
,
H. filipjevi
, and
H. latipons
populations, respectively. This is the first research to provide conclusive diagnostic tests for cyst nematode populations isolated from Turkey. These assays provide a sensitive, practical, and quick method for detecting
Heterodera
species and, therefore, have the potential to be utilized in the early identification of populations and monitoring of infestations without morphometric studies.
Wheat (Triticum spp.) is highly susceptible to the root lesion nematode, Pratylenchus thornei, which causes excessive
amounts of crop losses each year. In this research, we investigated the ...cumulative effect of the biocontrol agent
Purpureocillium lilacinum (syn: Paecilomyces lilacinus) against P. thornei. Three doses of P. lilacinum (106, 107 and
108 conidia cultures mL-1) with one dose of 400 P. thornei individuals (adults and juveniles) mL-1 were applied in 100
cm3 soil under greenhouse conditions. The number of nematodes in the soil and root in addition to total nematode in
soil+root were determined. Moreover, different plant parameters such as the plant height, plant fresh and dry weight,
root fresh and dry weight were evaluated. Applications with the higher dose of bio-agents (100 cm3 P. thornei infested
soil with 108 conidia culture of P. lilacinum mL-1) exhibited maximal enhancement in dry and fresh weight of shoot and
reduced P. thornei population. As a consequence, P. lilacinum individually was highly effective in enhancing different
plant parameters and suppressing P. thornei reproduction. Overall, present findings suggest that the exploitation of the
biocontrol agent P. lilacinum could be helpful for effective management of the root lesion nematode P. thornei.
Fungal species associated with crown and root rot diseases in wheat have been extensively studied in many parts of the world. However, no reports on the relative importance and distribution of ...pathogens associated with wheat crown and root rot in Kyrgyzstan have been published. Hence, fungal species associated with wheat crown/root rot were surveyed in three main wheat production regions in northern Kyrgyzstan. Fungal species were isolated on 1/5 strength potato-dextrose agar amended with streptomycin (0.1 g/L) and chloramphenicol (0.05 g/L). A total of 598 fungal isolates from symptomatic tissues were identified using morphological features of the cultures and conidia, as well as sequence analysis of the nuclear ribosomal internal transcribed spacer (ITS) region, the translation elongation factor 1α (
), and the RNA polymerase II beta subunit (
) genes. The percentage of fields from which each fungus was isolated and their relative percentage isolation levels were determined.
, the causal agent of common root rot, was the most prevalent pathogenic species isolated, being isolated from 86.67% of the fields surveyed at a frequency of isolation of 40.64%.
spp. accounted for 53.01% of all isolates and consisted of 12 different species. The most common
species identified was
, which was isolated from 70% of the sites surveyed with an isolation frequency of 21.57%, followed by
,
,
, and
, all of which had a field incidence of more than 23%. Inoculation tests with 44 isolates representing 17 species on the susceptible
cv. Seri 82 revealed that
and
isolates were equally the most virulent pathogens. The widespread distribution of moderately virulent
appears to be a serious threat to wheat culture, limiting yield and quality. With the exception of
, the remaining
species did not pose a significant threat to wheat production in the surveyed areas because common species, such as
,
,
, and
, were non-pathogenic but infrequent species, such as
,
, and
, were highly or moderately virulent.
, which was found in three different fields, was mildly virulent. The remaining
species,
,
,
, and
, as well as
,
, and
, were non-pathogenic and considered to be secondary colonizers. The implications of these findings are discussed.
Several nematode species can be found in different densities in almost any soil ecosystem, and their diversity in those ecosystems depends on numerous reasons, such as climatic conditions and host ...presence. Cereals are one of the main hosts of plant-parasitic nematodes (PPN), chiefly root-lesion nematodes (RLN, Pratylenchus spp.) and cereal cyst nematodes (CCN, Heterodera spp.). These nematodes are known as major parasites of the cereal crops; however, agricultural areas accommodate various nematodes showing biological variation. The diversity of parasitic nematodes on cereals in the Sakarya provinces of Türkiye, where cereals are intensively grown and located in the middle of two climatic zones, has not been well studied. Therefore, in this study, we aimed to determine the diversity, identification, and molecular phylogeny of PPNs in wheat-growing ecosystems in the Hendek, Pamukova, Geyve, Akyazı, and Central districts of Sakarya. The diversity of PPNs was calculated using the Shannon diversity index. Thirteen PPN genera were detected in 92% of soil samples. Heterodera filipjevi was identified in 24% of the soil samples using morphological, morphometrical, and molecular tools. In the morphological and molecular analyses, intraspecific polymorphism was observed in H. filipjevi populations. The result indicated that the high infestation rate of H. filipjevi was recorded from Geyve and Pamukova, followed by Hendek and Akyazı; however, a low infestation rate was detected in the Central district. The moderate value of the Shannon index of migratory nematode species was obtained in wheat fields as 2.31, whereas the value of evenness was 0.93, implying moderate diversity and high evenness of nematodes. This study is the first comprehensive report on H. filipjevi from wheat cropping areas in the Sakarya province. Intensified cereal cropping systems with/without non-cereal rotations increased the risk of plant-parasitic nematodes, especially RLNs and H. filipjevi infection of wheat production areas in the province.
Wireworms (Coleoptera: Elateridae) are common insect pests that attack a wide range of economically important crops including potatoes. The control of wireworms is of prime importance in potato ...production due to the potential damage of the larvae to tuber quantity and quality. Chemical insecticides, the main control strategy against wireworms, generally fail to provide satisfactory control due to the lack of available chemicals and the soil-dwelling habits of the larvae. In the last decades, new eco-friendly concepts have emerged in the sustainable control of wireworms, one of which is entomopathogenic nematodes (EPNs). EPNs are soil-inhabitant organisms and represent an ecological approach to controlling a great variety of soil-dwelling insect pests. In this study, the susceptibility of
Linnaeus and
Brullé larvae, the most common wireworm species in potato cultivation in Türkiye, to native EPN strains
(Sc_BL22),
(Sf_BL24 and Sf_KAY4), and
(Hb_KAY10 and Hb_AF12) were evaluated at two temperatures (25 and 30 °C) in pot experiments.
Hb_AF12 was the most effective strain at 30 °C six days post-inoculation and caused 37.5% mortality to
larvae.
larvae were more susceptible to tested EPNs at the same exposure time, and 50% mortality was achieved by two EPNs species, Hb_AF12 and Sc_BL22. All EPN species/strains induced mortality over 70% to both wireworm species at both temperatures at 100 IJs/cm
, 18 days post-treatment. The results suggest that tested EPN species/strains have great potential in the control of
and
larvae.
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