Establishment and new hosts of the non-native seed beetle Stator limbatus (Coleoptera, Chrysomelidae, Bruchinae) on acacias in Europe

Stator limbatus is a phytophagous beetle native to warm regions of North and Central America, feeding on Fabaceae seeds and one of the most polyphagous species within the subfamily Bruchinae, here reported for the first time in Europe and on new hosts. Adult beetles emerged from Acacia spp. seeds collected in the islands of Corsica (France), and Sardinia (Italy). The wide presence in Sardinia and Corsica supports the hypothesis that this alien species was introduced several years ago. In both islands, S. limbatus emerged from Acacia mearnsii seeds, with infestation rates of up to 74.2 and 90.8% in 2019 and 2020, respectively. This seed beetle also emerged from two previously unreported host species, Acacia saligna and A. pycnantha, showing highest infestation rates of 4.0 and 95.1%, respectively. Both Acacia species are reported as new host associations with S. limbatus. Overall, seed infestation rates recorded in 2019 and 2020 indicate that S. limbatus is well established and that Mediterranean bioclimatic conditions are suitable for its population increase in size. This study lays the foundations for further research on known and potential host species and the spread and distribution of S. limbatus in Europe.

Auto-resistance to germination of invasive Acacia saligna trees seeds to Al-Jabal Al-Akhdar region

Sustaining the vegetation cover in Libya represents the most important priority that must be taken into account by the Ministry of Agriculture. This study was conducted in the laboratory of the Department of Biology, Faculty of Education, Omar Al-Mukhtar University, Al-Bayda, Libya, to investigate the possibility of controlling seed germination of Acacia saligna trees by using aqueous extracts (flower- seeds- leaves - bark) at different concentration (10, 20 and 40%). The results showed highly significant differences in decreasing a germination percentage and increasing an average germination time, between aqueous extracts and concentrations relative to control, where a flowers extract gave the largest effect on inhibitory germination percentages over the rest of other extracts. Commonly 40% concentration was the most toxic effect on A.saligna seed germination. The study concluded of Acacia salgina trees possess an autotoxicity that can be used to combat thier invasion and expansion in agricultural lands

Acacia saligna (Port Jackson wattle).

A. saligna is a fast-growing, nitrogen-fixing large shrub or small tree from southwestern Western Australia. It coppices readily and is tolerant of calcareous, alkaline and saline soils in temperate climates. A. saligna is planted in North Africa, the Middle East and South America for fodder, fuelwood, sand stabilization and as a windbreak. In Australia it is most commonly used as an ornamental, but is being increasingly planted in agroforestry systems for fodder production and soil conservation.

Uromycladium spp. that cause gall rusts (Acacia gall rusts).

Gall forming rust fungi of the genus Uromycladium are native to Australasia. They are invasive in New Zealand, the Philippines, East Timor, Malaysia and Indonesia. Uromycladium murphyi (as Uromycladium notabile in the literature) causes damage to Acacia decurrens grown for tannin and as an ornamental in New Zealand. Other hosts of U. murphyi are A. baileyana, A. dealbata and A. mearnsii. Uromycladium paradoxae infects Acacia paradoxa in New Zealand. Uromycladium species have been found in New Zealand on A. ulicifolia and A. verticillata, but the taxa on these two hosts is uncertain and await phylogenetic studies. Uromycladium falcatariae causes serious disease in Falcataria moluccana in Southeast Asia. This tree is grown as a shade tree in coffee plantations, for timber and pulp, and for other uses. Uromycladium morrisii and U. woodii were deliberately introduced into South Africa for the biological control of Acacia saligna and Paraserianthes lophantha, respectively.

Effects of a Trench as a Moisture Harvesting Structure on the Biomass Production and Growth of Trees Planted to Restore Degraded Land, Southern Ethiopia

Knowledge about the biomass productivity of trees planted in a rainwater harvesting structure, i.e., a trench (T), relative to a normal pit (P) on degraded land is scarce. The objective of this research paper is to compare the effect of T with P on the growth and biomass production of the Acacia saligna and Casuarina equisetifolia which were planted on degraded land. All the individual stems of both species in the T and P, their diameters at breast height (DBH) and heights in 2016 and 2020 were measured. Species-specific allometric equations were used to quantify the biomass production of the studied species. The t-tests were used for data analysis; both A. saligna and C. equisetifolia individuals planted in the T had higher DBH and height increment as compared with A. saligna and C. equisetifolia that were planted and grown in a P. The results also revealed significant differences on the mean DBH and height of A. saligna and C. equisetifolia planted in a T and P (p < 0.05). Between 2016 and 2020, the total biomass (TB) of A. saligna planted in a T and in a P increased significantly (p < 0.05) on average by 25.5 kg/tree and 7.7 kg/tree, respectively (p < 0.05). Similarly, the mean TB values of the C. equisetifolia planted in a T and a P between 2016 and 2020 increased significantly (p < 0.05) by 28.9 kg/tree and 13.1 kg/tree, respectively. Finally, establishing trenches to restore degraded lands was shown to facilitate growth and biomass production of planted species on degraded land.