This study evaluated the mycoherbicidal potential of Alternaria alternata(Fries.) Kiessler on cocklebur (Xanthium strumarium L.), a noxious weed in Algeria. Conidial suspension, a rapeseed-oil-based liquid formulation and a sodium-alginate-based solid formulation, all with 10(6) conidia/ml, as well as the herbicide (Mustang(R)) at a reduced dose (0.45 L/ha) were compared. Inoculum was applied on detached leaves of cocklebur under laboratory conditions and on 4-5 leaf stage cocklebur seedlings in pots in a greenhouse and in the field. Disease severity was highest following application of the liquid formulation in the detached leaf assay (95.5%) as well as in the pot (80%) and field (43%) experiments. Similarly, the oil-based liquid formulation reduced cocklebur height, root length and dry weight by up to 50%, 27% and 58%, respectively in pot trial and 40%, 51% and 45%, respectively in the field experiment. The conidial suspension ranked second in efficacy, followed by the solid formulation. Mustang(R) showed the highest herbicidal effect. None of the crops tested for host specificity including tomato, wheat, faba bean and zucchini was susceptible to the fungus. Our findings suggest that A. alternatahas potential as biocontrol agent of cocklebur especially when applied in an oil-emulsion-based formulation.

Pomegranate heart rot (black heart) was observed in several pomegranate-growing areas of Algeria. From 2022 to 2025, surveys were conducted across 15 provinces (20 localities), and a total of 85 fruits (symptomatic and asymptomatic) were collected. Fruits were cut transversely to assess internal symptoms, ranging from early aril browning to dry black rot. Thirty Alternaria isolates were obtained and grouped into four morphotypes based on colony and conidial morphological traits. A subset of 18 isolates was analysed by multilocus phylogeny (ITS, EF-1α, GAPDH and OPA10-2); all analysed isolates clustered within the Alternaria alternata species complex, in the clade including the ex-type strain CBS 916.96. Fruit pathogenicity tests with Algerian isolate GA reproduced typical internal heart rot symptoms, and the pathogen was consistently re-isolated from symptomatic tissues. In fruit inoculations with isolate GA, cultivars differed in susceptibility, with mean disease severities of 94%, 62% and 9.5% in ‘Taferrante’, ‘Ikhessène’ and ‘Kares’, respectively, expressed as the percentage of the fruit section presenting rot symptoms. Detached leaf assays indicated isolate-dependent differences in aggressiveness, and ‘Kares’ showed the lowest susceptibility. Overall, the results confirm that A. alternata is the causal agent of pomegranate heart rot in Algeria and provide baseline information for disease diagnosis and management.