Mechanism of Seed Transmission and Seed Infection in Major Agricultural Crops in India

2020 ◽  
pp. 749-791
Author(s):  
P. Nallathambi ◽  
C. Umamaheswari ◽  
Sandeep K. Lal ◽  
C. Manjunatha ◽  
J. Berliner
Keyword(s):  
Seed Transmission ◽  
Seed Infection ◽  
Agricultural Crops

scholarly journals Seedborne Infection of Rice by Pyricularia oryzae and Its Transmission to Seedlings

Plant Disease ◽  
1998 ◽  
Vol 82 (10) ◽  
pp. 1093-1099 ◽  
Author(s):  
H. K. Manandhar ◽  
H. J. Lyngs Jorgensen ◽  
V. Smedegaard-Petersen ◽  
S. B. Mathur
Keyword(s):  
Low Temperature ◽  
Transmission Rate ◽  
Seed Transmission ◽  
Pyricularia Oryzae ◽  
Infection Frequency ◽  
Seed Infection ◽  
Percent Recovery ◽  
Unsterilized Soil ◽  
Lower Infection ◽  
Germinating Seeds

Seedborne infection of rice by Pyricularia oryzae and its transmission to seedlings were studied quantitatively with naturally infected seeds of three rice cultivars collected from three locations in Nepal. A linear relationship on a logistic scale was found between panicle symptoms and seed infection, i.e., the more symptoms the higher seed infection. However, healthy-looking panicles and branches of panicles could also yield infected seeds. Postharvest measures such as winnowing and sun-drying significantly reduced seed infection by P. oryzae and filled grains had a lower degree of infection than unfilled grains. Sporulation of P. oryzae was most often confined to the embryonal end of germinating seeds. In contrast, most of the nongerminating seeds had sporulation all over the seed surface. Transmission of P. oryzae from seeds to seedlings, studied under various seeding conditions, showed that the transmission rate was always low. Thus, a seed sample with 21% seed infection resulted in less than 4% seedlings with blast lesions. Seed transmission was found for light covering of the seeds with soil or for moist seeding without covering. Transmission was rarely found when seeds were completely covered, and never in seedlings raised under water seeding conditions. Lower infection frequency was observed in seedlings raised in unsterilized soil than in seedlings raised in sterilized soil. Also, percent recovery of P. oryzae from infected seeds was higher in sterilized soil than in unsterilized soil and declined with time. Seedlings grown under low temperature (15 to 20°C) conditions did not develop blast lesions but when the same plants were transferred to high temperature (25 to 30°C) conditions, blast lesions were detected. This confirmed the latent infection in seedlings by P. oryzae grown under low temperature conditions.

TOLERANCE LEVEL OF ALTERNARIA SESAMI AND THE EFFECT OF SEED INFECTION ON YIELD OF SESAME IN KENYA

2000 ◽  
Vol 36 (3) ◽  
pp. 335-342 ◽  
Author(s):  
P. S. OJIAMBO ◽  
P. O. AYIECHO ◽  
R. D. NARLA ◽  
R. K. MIBEY
Keyword(s):  
Disease Severity ◽  
Leaf Spot ◽  
Seed Weight ◽  
Sesame Seed ◽  
Seed Transmission ◽  
Gompertz Model ◽  
Major Effect ◽  
Seed Infection ◽  
Tolerance Level ◽  
Seed Increase

Field plots of sesame (Sesamum indicum) with six different levels of seed infection with Alternaria sesami were monitored for Alternaria leaf spot severity at Kibwezi, eastern Kenya. The aim of the study was to determine the effect of seed transmission of the pathogen on yield and tolerance level of the fungus in sesame seed. Increase in percentage leaf area diseased and percentage defoliation fitted the Gompertz model more closely than the logistic model. Areas under disease progress curves (AUDPC), infection and defoliation rates varied among the six infection levels. Disease severity increased with increase in seed infection and was least and most severe in plots established with seeds with 0 and 8% infection levels respectively. Yields ranged from 234.9 to 300.1 kg ha−1 compared with 312.5 kg ha−1 for the control, and losses due to seed infection ranged from 4% to 25%. Disease severity was negatively correlated with seed yield, 1000-seed weight and seeds per capsule. Alternaria leaf spot severity had a major effect on the seed weight component of yield. Tolerance level of A. sesami in sesame seed was determined to be less than 2%.

Effects of timings of inoculation with Mycosphaerella pinodes on yield and seed infection of field pea

1997 ◽  
Vol 77 (4) ◽  
pp. 685-689 ◽  
Author(s):  
A. G. Xue ◽  
T. D. Warkentin ◽  
E. O. Kenaschuk
Keyword(s):  
Pisum Sativum ◽  
Seed Weight ◽  
Field Experiments ◽  
Control Program ◽  
Seed Transmission ◽  
Field Pea ◽  
Mycosphaerella Pinodes ◽  
Yield Reduction ◽  
Seed Infection ◽  
Flowering Stage

Inoculated field experiments were carried out in 1994 and 1995 to study the effect of the timing of inoculation with Mycosphaerella pinodes (Berk. & Bloxam) Vestergren on disease development, yield reduction and seed infection, in three field pea (Pisum sativum L.) cv. Bohatyr, cv. Scorpio and cv. Triumph. The greatest impact of inoculation on all disease and yield parameters was at the 8–10 node stage in 1994, and at the mid-flowering stage in 1995. The lowest impact of inoculation was at the pod swell stage for both years. When inoculated at 8–10 nodes, mid-flowering and pod swell stages, M. pinodes reduced yield by 31, 24 and 19%, respectively, in 1994 and 33, 43 and 30%, respectively, in 1995. The 1000-seed weight was not affected by the timing of inoculation; however, all inoculations reduced seed weight in both years. Plant-to-seed transmission of M. pinodes was affected by the timing of inoculation in 1994, but not in 1995. Results of this study suggest that prevention of early infection by M. pinodes will provide the best economic return in a mycosphaerella blight control program on field pea. Key words: Mycosphaerella blight, Mycosphaerella pinodes, field pea, Pisum sativum, yield reduction

scholarly journals Seed Transmission of Hibiscus Latent Ringspot Virus (HLRSV)

Plant Disease ◽  
1997 ◽  
Vol 81 (9) ◽  
pp. 1082-1084 ◽  
Author(s):  
C. Rubies-Autonell ◽  
M. Turina
Keyword(s):  
Seed Transmission ◽  
Abutilon Theophrasti ◽  
Hibiscus Cannabinus ◽  
Ringspot Virus ◽  
Seed Infection ◽  
Chenopodium Amaranticolor ◽  
Commercial Seed ◽  
Immunosorbent Assays ◽  
Systemic Symptoms ◽  
Greenhouse Tests

Commercial seed lots of various cultivars of kenaf (Hibiscus cannabinus) were shown to transmit hibiscus latent ringspot virus (HLRSV) to progeny seedlings in different percentages up to a maximum of 26%. In these greenhouse tests, no symptoms were observed in the infected seedlings. Enzyme-linked immunosorbent assays (ELISA) of dissected kenaf seeds suggested that seed infection occurs through the embryo. HLRSV was also shown to be seed transmitted in Chenopodium amaranticolor and C. quinoa, in 11% and in less than 1%, respectively, of the seed collected from mechanically inoculated plants. However, transmission of HLRSV through seed was not detected in Abutilon theophrasti. C. quinoa and C. amaranticolor plants infected through seed transmission were invariably symptomless as opposed to mechanically inoculated plants that exhibited systemic symptoms of yellow flecking.

scholarly journals Occurrence of the White Rust Pathogen, Albugo tragopogonis, in Seed of Sunflower

Plant Disease ◽  
1999 ◽  
Vol 83 (1) ◽  
pp. 77-77 ◽  
Author(s):  
A. Viljoen ◽  
P. S. van Wyk ◽  
W. J. Jooste
Keyword(s):  
Helianthus Annuus ◽  
South African ◽  
Long Range ◽  
Seed Transmission ◽  
Field Trials ◽  
Seed Infection ◽  
Causal Organism ◽  
White Rust ◽  
Epidermal Tissue ◽  
Rust Pathogen

White rust of sunflower (Helianthus annuus L.), caused by Albugo tragopogonis (Pers.) S. F. Gray, appeared in South African fields not previously planted to sunflower. Spread to these fields from infested fields was unlikely, as some of the newly affected fields were planted out of season and were more than 300 km away from other sunflower production fields. Several reports of this nature led us to investigate the possibility of seed transmission of the causal organism. Extensive colonization of sunflower heads by A. tragopogonis was observed in field trials and breeding nurseries. Head infections consisted of two distinct lesion types. White rust pustules, typical of those formed on abaxial sides of leaves, were recognized on abaxial sides of involucral bracts. Grayish, localized lesions containing dark-colored oospores of the fungus, similar to those formed on stems and petioles (1), were produced in sub-epidermal tissue and extended 3 to 5 mm deep into receptacles. Colonization of seeds was found in only a few lines. Oospores were produced in the pericarps and testae of seeds. No oospores or hyphae, however, were observed in the embryo. This is the first report of A. tragopogonis being seed-borne. Since the incidence of seed infection is low, spread of disease to infested fields is expected to be insignificant. Of more concern, however, is the possible long-range dissemination of the fungus by means of infected seed into regions or countries where the disease has not been previously reported. Reference: (1) P. S. Van Wyk et al. Helia 18:83, 1995.

scholarly journals Re-evaluation of Seed Transmission of Clavibacter michiganensis subsp. nebraskensis in Zea mays

Plant Disease ◽  
2019 ◽  
Vol 103 (1) ◽  
pp. 110-116 ◽  
Author(s):  
Charles C. Block ◽  
Lisa M. Shepherd ◽  
Gladys C. Mbofung-Curtis ◽  
Jeff M. Sernett ◽  
Alison E. Robertson
Keyword(s):  
Zea Mays ◽  
Transmission Rate ◽  
Seed Transmission ◽  
Disease Spread ◽  
Seed Infection ◽  
Clavibacter Michiganensis ◽  
Long Distance ◽  
Corn Seed ◽  
Infected Seed ◽  
Clavibacter Michiganensis Subsp

The spread of Goss’s bacterial wilt and leaf blight of corn (Zea mays), caused by Clavibacter michiganensis subsp. nebraskensis, to a wider geographic range in the early 2000s compared with the late 1960s has generated concern about the possible role of seed transmission in long-distance spread. The objectives of this research were: (1) to determine the percentage of seed infection found in seed harvested from inoculated and noninoculated plants of hybrids that varied in resistance to Goss’s wilt; and (2) to estimate the seed transmission rate from these infected seed lots. The greatest percent seed infection was detected in seed from inoculated plants of the most susceptible hybrid and the least in seed from the most resistant hybrid. Seed lots with seed infection that ranged from 3.6 to 37.0% were planted in three field and three greenhouse trials. A total of 12 seed transmission events (Goss’s wilt symptomatic seedlings) were identified among 241,850 plants examined, for a seed transmission rate of 0.005%. When the seed transmission rate was recalculated to consider only the infected seed portion of each seed lot, the rate increased to 0.040% (12 events from 30,088 potentially infected plants). Based on the low seed transmission rate observed and previous research on disease spread from a point source, it seems unlikely that seed transmission could introduce enough inoculum to create a serious disease outbreak in a single growing season. However, risk of seed transmission is relevant for phytosanitary restrictions and preventing the introduction of the pathogen to new areas. To date, Goss’s wilt has not been detected outside North America, and while the risk of seed transmission is very low, the risk is not zero. Fortunately, the presence of C. michiganensis subsp. nebraskensis in corn seed is readily detectable by established seed health testing methods.

scholarly journals Quantifying Effects of Seedborne Inoculum on Virus Spread, Yield Losses, and Seed Infection in the Pea seed-borne mosaic virus–Field Pea Pathosystem

2009 ◽  
Vol 99 (10) ◽  
pp. 1156-1167 ◽  
Author(s):  
B. A. Coutts ◽  
R. T. Prince ◽  
R. A. C. Jones
Keyword(s):  
Mosaic Virus ◽  
Seed Yield ◽  
Seed Transmission ◽  
Seed Infection ◽  
Virus Spread ◽  
Yield Losses ◽  
Seeding Rate ◽  
Transmission Rates ◽  
Infected Seed ◽  
Pea Seed

Field experiments examined the effects of sowing field pea seed with different amounts of infection with Pea seed-borne mosaic virus (PSbMV) on virus spread, seed yield, and infection levels in harvested seed. Plots were sown with seed with actual or simulated seed transmission rates of 0.3 to 6.5% (2005) or 0.1 to 8% (2006), and spread was by naturally occurring migrant aphids. Plants with symptoms and incidence increased with the amount of primary inoculum present. When final incidence reached 97 to 98% (2005) and 36% (2006) in plots sown with 6.5 to 8% infected seed, yield losses of 18 to 25% (2005) and 13% (2006) resulted. When incidence reached 48 to 76% in plots sown with 1.1-2 to 2% initial infection, seed yield losses were 15 to 21% (2005). Diminished seed weight and seed number both contributed to the yield losses. When the 2005 data for the relationships between percent incidence and yield or yield gaps were plotted, 81 to 84% of the variation was explained by final incidence and, for each 1% increase, there was a yield decline of 7.7 to 8.2 kg/ha. Seed transmission rates in harvested seed were mostly greater than those in the seed sown when climatic conditions favored early virus spread (1 to 17% in 2005) but smaller when they did not (0.2 to 2% in 2006). In 2007, sowing infected seed at high seeding rate with straw mulch and regular insecticide application resulted in slower spread and smaller seed infection than sowing at standard seeding rate without straw mulch or insecticide. When data for the relationship between final percent incidence and seed transmission in harvested seed were plotted (all experiments), 95 to 99% of the variation was explained by PSbMV incidence. A threshold value of <0.5% seed infection was established for sowing in high-risk zones.

Phoma insidiosa. [Descriptions of Fungi and Bacteria].

1972 ◽  
Author(s):  
E. Punithalingam
Keyword(s):  
South Africa ◽  
Triticum Aestivum ◽  
Puerto Rico ◽  
Sierra Leone ◽  
Geographical Distribution ◽  
Seed Transmission ◽  
Saccharum Officinarum ◽  
Seed Infection ◽  
Subsequent Growth ◽  
A Minor

Abstract A description is provided for Phoma insidiosa. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Sorghum spp., Oryza sativa, Saccharum officinarum, Setaria, Triticum aestivum and Zea mays. DISEASE: A minor leaf spot of Sorghum and Setaria spp. and other Gramineae. The macroscopic symptoms are variable and not particularly distinctive. Leaf lesions have an irregular outline, sometimes beginning at the tip or edge, and are brown to grey with narrow redish-purple margins. The scattered pycnidia occur sometimes in clusters or lines, interveinally. Spotting and pycnidia form on grain and glumes. GEOGRAPHICAL DISTRIBUTION: Argentina, Australia (W.), Brazil, Canada, China, Cuba, Ethiopa, Hawaii, India, Jamaica, Kenya, Laos, Malawi, Malaysia (W.), Nepal, Nigeria, Puerto Rico, Rhodesia, Senegal, Sierra Leone, South Africa, Sudan, Tanzania, Uganda, USA, USSR, Venezuela, Zaire Republic, Zambia. The fungus may be detected on introduced seed. TRANSMISSION: Probably carried on the seed; infection of the seed reduces both germination and subsequent growth. May remain viable on seed for 1 yr.

Rational nature management - the basis for increasing the stability of agricultural crops for diseases and pests

2019 ◽  
Vol 325 (5) ◽  
pp. 65-69
Author(s):  
I.A. Trofimov ◽  
◽  
V.M. Kosolapov ◽  
L.S. Trofimova ◽  
E.P. Yakovleva ◽  
...  
Keyword(s):  
Nature Management ◽  
Agricultural Crops ◽  
Rational Nature ◽  
The Stability

SPECIES, HOST RANGE, AND IDENTIFICATION KEY OF WHITEFLIES OF BOGOR AND SURROUNDING AREA

2019 ◽  
Vol 18 (2) ◽  
pp. 127
Author(s):  
Purnama Hidayat ◽  
Denny Bintoro ◽  
Lia Nurulalia ◽  
Muhammad Basri
Keyword(s):  
Host Range ◽  
Host Plants ◽  
Ornamental Plants ◽  
Identification Key ◽  
Agricultural Crops ◽  
Surrounding Area ◽  
Aleurodicus Dispersus ◽  
Agricultural Plants ◽  
Surrounding Areas ◽  
Forest Plants

Species identification, host range, and identification key of whiteflies of Bogor and surrounding area. Whitefly (Hemiptera: Aleyrodidae) is a group of insects that are small, white, soft-bodied, and easily found on various agricultural crops. Whitefly is a phytophagous insect; some species are important pests in agricultural crops that can cause direct damage and can become vectors of viral diseases. The last few years the damage caused by whitefly in Indonesia has increased. Unfortunately, information about their species and host plants in Indonesia, including in Bogor, is still limited. Kalshoven, in his book entitled Pest of Crops in Indonesia, published in the 1980s reported that there were 9 species of whitefly in Indonesia. The information on the book should be reconfirmed. Therefore, this study was conducted to determine whitefly species and its host plants in Bogor and its surroundings. Whiteflies is identified based on the ‘puparia’ (the last instar of the nymph) collected from various agricultural plants, ornamental plants, weeds, and forest plants. A total of 35 species of whiteflies were collected from 74 species and 29 families of plants. The collwcted whiteflies consist of four species belong to Subfamily Aleurodicinae and 31 species of Subfamily Aleyrodinae. The most often found whitefly species were Aleurodicus dispersus, A. dugesii, and Bemisia tabaci. A dichotomous identification key of whiteflies was completed based on morphological character of 35 collected species. The number of whitefly species in Bogor and surrounding areas were far exceeded the number of species reported previously by Kalshoven from all regions in Indonesia.

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