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Sugarcane streak mosaic virus (SCSMV; Poaceavirus; Potiviridae) is the causal agent of streak mosaic disease of sugarcane (Saccharum interspecific hybrids), a major industrial crop that is widely cultivated in tropical and subtropical regions for sugar and ethanol production. was first reported by Hall et al. (1998) from quarantined germplasm material exhibiting mosaic symptoms imported from Pakistan into the USA. Subsequently, the virus was also reported to occur in most of the Asian countries like Bangladesh, India, Indonesia, Iran, Sri Lanka, Thailand, Vietnam and China (Chatenet et al. 2005; Hema et al. 2008, Kasemsin et al. 2016, Putra et al. 2014, Xu et al. 2010, Moradi et al. 2015; Moradi et al. 2018, Zhang et al. 2018). Until now, there is no report of SCSMV outside the Asian continent. From February to October 2018, sugarcane plants exhibiting symptoms such as irregular yellow and green mosaic, interveinal chlorotic specks, and streaks were observed in Bafing (Borotou-Koro), Marahoué (Zuénoula) and Tchologo (Ferkéssédougou) regions of Côte d'Ivoire (Fig. 1a). Varieties under large-scale commercial cultivation such as R570, R579, SP711406, Co997, Co449, M1176/77, M2593/92, M2580/95, and M1400/86 were all symptomatic. A total of 94 sugarcane leaf samples were collected from these regions and, among those, 82 showed disease symptoms and 12 were symptomless. Samples were first tested for the presence of sugarcane mosaic virus (SCMV), which causes mosaic a disease that is already present in Africa. Serological tests with infected sap using a Double Antibody Sandwich (DAS)- Enzyme Linked Immuno Sorbent Assay (ELISA) kit (DSMZ, RT-0166, Braunschweig, Germany) were negative for SCMV and no amplification product was obtained by RT-PCR using primers specific to the coat protein (CP) gene of SCMV (Putra et al. 2003). The 82 symptomatic leaves tested positive by DAS-ELISA with SCSMV antiserum (polyclonal antibodies were graciously provided by Prof. Hema M. of the Sri Venkateswara University, Tirupati, AP, India), whereas the 12 symptomless samples tested negative. To confirm these results, virus free greenhouse-grown sugarcane varieties Co997 and M1176/77, were mechanically inoculated with 10 sap extracts from 10 SCSMV-infected sugarcane leaf samples. Sap was also extracted from DAS-ELISA negative sugarcane leaves and used as negative control. For sap preparation, leaves were homogenized with a mortar in 2 mL of phosphate buffer 0.01 M pH 7.2 (ratio 1:10). Fifteen 4-week-old plants per variety were inoculated separately with each sap. All inoculated plants exhibited streak mosaic symptoms 13 days post-inoculation (fig. 1b), and the presence of SCSMV in the inoculated plants was confirmed by DAS-ELISA. Total RNA was extracted from four symptomatic leaf samples, one symptomless and one DAS-ELISA positive sample using TRIzol reagent (Invitrogen, Carlsbad, CA, USA). cDNA was synthesized using M-MLV Reverse Transcriptase (Promega, Cat.No.M1705, Madison, WI, USA) following the manufacturer's instructions. A 690-nucleotide fragment of the CP gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR) with primers SCSMV-F690 and SCSMV-R690 (Viswanathan et al. 2008). All primers were synthesized by Eurogentec (Seraing, Belgium). Aliquots of RT-PCR products (5 μl) were analyzed by electrophoresis on 1.2 % (w/v) agarose gel, stained with ethidium bromide and visualized on a UV transilluminator (Fig. 2). An amplification product of the expected size was obtained for all five symptomatic or DAS ELISA positive but not for the symptomless sample. Two RT-PCR products were sequenced and deposited in GenBank under accession Nos. LR594547 and LR594582. These partial CP gene sequences shared highest nucleotide identity with two isolates of SCSMV from India in GenBank: 91% with JN315855 and 90% with EF655859, thus confirming that SCSMV was occurring in sugarcane in Côte d'Ivoire. To our knowledge, this is the first report of natural infection of sugarcane by SCSMV in Africa. Streak mosaic is a serious threat to the entire sugar industry in West Africa and needs further investigations as it may affect sugarcane yields and impact local economies. Our findings further illustrate the need to develop virus-free germplasm for local, national, and international distribution of sugarcane.

Two generation mean analyses were used to assess the inheritance of partial resistance to black root rot in burley tobacco. A cultivar moderately resistant to black root rot, KY 14, was crossed with a cultivar with low resistance, Burley 21, and with a susceptible cultivar, Judy's Pride. Five-week-old seedlings of the parental, F 1 , F 2 , and both backcross generations for each cross were transplanted into soil infested with 100 chlamydospores of Thielaviopsis basicola per gram of soil mixture and grown in the greenhouse at 21 C. Percent root necrosis was estimated 3 wk after transplanting

Basidiocarps of C.p. developed in 4-5 wk on mycelial mats supported by sterilized pieces of witches' brooms from cacao, and mats continued to produce basidiocarps for an additional 8 wk. Multibasidiospore and single-basidiospore isolates of the fungus from T.c., Solanum spp. and lianas produced basidiocarps on mycelial mats

(...) In three greenhouse experiments and a field test, germ plasms F1002 and F1004, selected for resistance to P.b. and B.c., also possessed a moderate level of resistance to R.s. F1002 was selected originally from a USSR germ plasm that had been developed for resistance to storage rot caused by B.c. In a storage rot evaluation experiment, germ plasm FC712 was as resistant to P.b. and B.c. as were germ plasms developed specifically for resistance to storage rot (...)

(...) PStV-Ts induced severe mosaic and sytemic necrotic symptoms differing from the stripe symptoms induced by PStV-Tc and previously described PStV isolates. The biological properties of PStV-Ts were very similar to those of PStV-Tc and other known PStV isolates. Seed transmission rates of PStV-Ts in peanut averaged 12.5%. The purified capsid and cylindrical inclusion proteins of PStV-Ts consisted of single species of protein monomer with molecular weights of 36,000 and 71,000 respectively. In serological tests, PStV-Ts was indistinguishable from PStV-Tc and two PStV isolates from the United States but different from 14 other potyviruses

Leaves (7-9 cm long) from healthy tobacco plants were excised, surface-sterilized for 30 sec in a 0.05% NaOCl 3 solution and inoculated with four mycelial plugs of 2-day-old P. p. var. nicotianae cultures grown on oatmeal agar.(...) Genotype rankings for lesion development and percentage of infected leaf area were similar to known rankings of the same genotypes for field resistance

whiteflies were killed with malathion Pacumbaba, R. P. 1985. Virus-free shoots from cassava stem cuttings infected with cassava latent sprays after 8 hr of feeding on the test virus. Plant Disease 69:231-232. plants. Ten and 15 symptomless, unsevered Cassava stem cuttings infected with cassava latent virus (CLV) gave rise to shoots that showed CLV shoots in the first and second year of the symptoms at emergence, shoots that showed CLV symptoms 3-5 wk later, and shoots that remained symptomless after 6 wk of observation. CLV symptoms appeared 5-11 days earlier when experiment, respectively, were also symptomless shoots were detopped than when they were left intact. Symptomless shoots severed 2 detopped the third week after shoots wk after emergence from CLV-infected stem cuttings and subsequently detopped did not develop emerged from the ground. An equal CLV symptoms. These plants, however, readily developed symptoms of CLV when colonized with number of unsevered symptomless shoots CLV-laden Bemisia tabaci. Therefore, symptomless shoots were considered free of CLV and could that were not detopped served as be used as healthy planting stock. controls.

Resultats d'essais de lutte contre Phytophthora parasitica sur le tabac avec le metalaxyl ou d'autres fongicides systemiques en melange avec des nematicides/insecticides ainsi qu'avec le metalaxyl en combinaison avec des fumigants du sol

Disease development was evaluated Reuveni, M., Nesmith, W. C., and Siegel, M. R. 1986. Symptom development and disease severity after inoculation of the upper leaf in Nicotiana tabacum and N. repanda caused by Peronospora tabacina. Plant Disease 70:727-729. surfaces of 7-wk-old plants of Ky- 14 and N. repanda. Plants were sprayed die until 60 days after inoculation. Lesions (local and systemic) on N. repanda were capable of of inoculum was applied to three or four sporulating anytime between 7 and 60 days after inoculation. Virulence of P. tabacina to N. leaves per plant, using six plants of each repanda, but not to Ky-14, was greatly affected by the host plant from which inoculum was species. After inoculation, plants were obtained. When inoculum was harvested from Ky-14, blue mold on N. repanda was two to three covered with plastic bags, sprayed lightly times more severe than when the source of inoculum was from N. repanda. These data suggest that with distilled water, and incubated at 19 N. repanda could be an ideal host of P. tabacina and a significant inoculum source over a long C for 20 hr in the dark. Plants were then period. uncovered and kept in a growth chamber (23 C, 60-70 AE s-' m 2 , 12 hr of light

Bacterial pathogens have not been reported in association with Theobroma cacao. However, three strains of Agrobacterium tumefaciens isolated from chrysanthemum induced galls in seedling cacao plants grown in a greenhouse. Since T. cacao is thus a proven host for the crown gall bacterium, the Ti plasmid of A. tumefaciens may possibly be used as a vector for the introduction of selected DNA into cacao

Etude comparee d'un traitement a l'eau chaude et d'un traitement fongicide pour la lutte contre Alternaria sur Carthamus tinctorius

Disease severity and lesion number were lowest when fungicide sprays were initiated before flowering of the potato plant. Lowest disease incidence and highest yield of U.S. no. 1 tubers occurred in plots with low inoculum density and in plots were fungicide sprays were initiated before flowering. Whereas fungicide spray schedules had a significant effect on yield in 1985, there was no effect on yield in 1986