Atmospheric Warming-Associated Phenological Earliness Does Not Increase the Length of Growing Season in Himalayan Trees

We present phenological data for two time periods (1985–1987 and 2014–2016) on major tree species (Shorea robusta, Pinus roxburghii, Myrica esculenta, Quercus leucotrichophora, Rhododendron arboreum, Quercus floribunda, and Machilus duthiei) occurring along an altitudinal gradient of 300–2,200 m asl of Himalayan forests (a data-deficient region identified by the IPCC, 2007), and show that bud break and leafing in trees has advanced at 0.20 days/year, which is associated with a significant (P < 0.001) increase in atmospheric temperature (0.038°C/year) over the years in the study area. Also, the leaf drop period has advanced correspondingly (0.40 days/year); hence, the length of season (LOS) did not increase in these trees. This finding is contrary to the report of increase in LOS due to climatic warming from temperate latitudes of the world and satellite-based studies in Himalayan region. Arguably, phenomena such as bud break and leafing may not be captured by remote sensing, which is critical for determining the impact of climate change on the forest vegetation of the eco-sensitive Himalayan region. We suggest that this phenological earliness may alter forest structure and functioning and associated ecosystem services of these forests in the long run. Study Implications: This study suggests that bud break and leafing in trees has advanced, an advancement that is associated with the significant increase in atmospheric temperature over the years in the study area. However, the leaf drop period has advanced correspondingly; hence, the length of season of trees in the study area did not increase. Nonetheless, the earliness in the leafing and leaf drop have potential implications on forest ecosystem structure and functioning, such as photosynthesis, carbon assimilation, increased asynchrony in plant-pollinators and animal interactions, reproduction success, and herbivory that require further detailed investigation. Warming may also advance seed maturation and desiccation of seeds that may disrupt the synchrony between monsoon and tree seed germination, forest regeneration, and ensuing ecosystem services. Generalizations on a regional scale on the impact of climate change on annual patterns of growth of forests that are based on remote-sensing studies could mask the impact of the premonsoon period, when bud break and leafing take place. These impacts may not be captured by remote sensing; impacts which, in this study, we have found to be critical.

Coniothyrium glycines (red leaf blotch).

Red leaf blotch affects soyabean in central and southern Africa. The disease and the causal fungus (Coniothyrium glycines) were first reported in Ethiopia in 1957. C. glycines is native to Africa, living on the native legume, Neonotonia wightii, and perhaps other native or non-native legumes. The jump of the pathogen to soyabean occurred as early as 1957 and reports of the occurrence of red leaf blotch have increased along with soyabean production in Africa. The disease is currently a serious threat to soyabean production in sub-Saharan African countries with losses of up to 70% reported. C. glycines is considered a threat to soyabean-producing countries such as Brazil and the USA. The pathogen is not known to be disseminated by seed or wind. Infection is thought to occur via rainsplash of soilborne inoculum onto the leaves of soyabean plants. Symptoms include characteristic dark red spots on the upper leaf surface and reddish-brown lesions with dark borders on the lower surface. Premature leaf drop may occur in heavy disease conditions, releasing sclerotia back into the soil. The disease is favoured by wet, humid conditions.

Podosphaera spiraeae (Japanese spiraea powdery mildew).

Podosphaera spiraeae is a common fungal pathogen for plants in the genus Spiraea. The pathogen is native to Japan but is most likely widespread throughout the temperate world where viable host plants occur. Identification of powdery mildew on Spiraea spp. can be difficult and its occurrence has not been well documented. Wind dispersal of asexual spores, known as conidia, spreads powdery mildew between viable host plants. The most likely long-distance pathway of invasion is through the nursery industry, which commonly trades Spiraea plants. P. spiraeae can be detrimental to nursery growers as it is unsightly, reduces photosynthesis and flower vigour and causes premature leaf drop. Primary control of the pathogenic fungus requires intricate integrated pest management regimes.

Coniothyrium glycines (red leaf blotch).

Red leaf blotch affects soyabean in central and southern Africa. The disease and the causal fungus (Coniothyrium glycines) were first reported in Ethiopia in 1957. C. glycines is native to Africa, living on the native legume, Neonotonia wightii, and perhaps other native or non-native legumes. The jump of the pathogen to soyabean occurred as early as 1957 and reports of the occurrence of red leaf blotch have increased along with soyabean production in Africa. The disease is currently a serious threat to soyabean production in sub-Saharan African countries with losses of up to 70% reported. C. glycines is considered a threat to soyabean-producing countries such as Brazil and the USA. The pathogen is not known to be disseminated by seed or wind. Infection is thought to occur via rainsplash of soilborne inoculum onto the leaves of soyabean plants. Symptoms include characteristic dark red spots on the upper leaf surface and reddish-brown lesions with dark borders on the lower surface. Premature leaf drop may occur in heavy disease conditions, releasing sclerotia back into the soil. The disease is favoured by wet, humid conditions.

Podosphaera spiraeae (Japanese spiraea powdery mildew).

Podosphaera spiraeae is a common fungal pathogen for plants in the genus Spiraea. The pathogen is native to Japan but is most likely widespread throughout the temperate world where viable host plants occur. Identification of powdery mildew on Spiraea spp. can be difficult and its occurrence has not been well documented. Wind dispersal of asexual spores, known as conidia, spreads powdery mildew between viable host plants. The most likely long-distance pathway of invasion is through the nursery industry, which commonly trades Spiraea plants. P. spiraeae can be detrimental to nursery growers as it is unsightly, reduces photosynthesis and flower vigour and causes premature leaf drop. Primary control of the pathogenic fungus requires intricate integrated pest management regimes.

Genetic diversity and pathogenicity of Verticillium dahliae isolates and their co-occurrence with Fusarium oxysporum f. sp. vasinfectum causing cotton wilt in Xinjiang, China

Cotton production in Xinjiang, the largest cotton producing area in China, has an increasingly serious disease threat from Verticillium dahliae. Eighty-five V. dahliae isolates were obtained from wilted cotton plants collected from 8 counties in Xinjiang. The isolates were assessed for genotypic diversity by DNA sequence analysis and PCR molecular genotyping with specific markers for race 1, race 2, defoliating (D) pathotype, non-defoliating (ND) pathotype, and mating type idiomorph Mat1-2. Isolates belonged to lineages 1A or 2B with 3 sub-genotypes found in each lineage. All isolates tested positive for race 2 and Mat1-2 markers. All isolates in lineage 2B tested positive for the ND pathotype marker, but only isolates in the major sub-genotype in lineage 1A tested positive for the D pathotype marker. Pathogenicity assays on Gossypium hirsutum ‘Acala 44’ demonstrated no significant difference among sub-genotypes within each lineage. Isolates in lineage 1A caused greater shoot weight reductions, % leaf drop, and % diseased leaves than isolates in lineage 2B. One isolate in each lineage for 1A and 2B was avirulent. Isolates in lineage 1A caused greater than 50% leaf drop and a 17 gram shoot weight reduction compared to a 9% leaf drop and a 6 gram shoot weight reduction by isolates in lineage 2B. Overall, 42% of the V. dahliae isolates from Xinjiang were D pathotype, but the percentage varied widely among locations. Two plants had both pathotypes. Nineteen isolates of Fusarium oxysporum f. sp. vasinfectum VCG0114 also were recovered from wilted plants in Xinjiang. Two plants had both Verticillium and Fusarium wilt pathogens. Both pathogens should be considered when using or developing wilt resistant/tolerant materials for Xinjiang.

PENGARUH PENGGUNAAN PACLOBUTRAZOL, KNO3 DAN ETEFON PADA PEMACUAN PEMBUNGAAN TANAMAN MANGGIS (Garcinia mangostana L.)

Mangosteen (Garcinia mangostana L.) is a tropical plant that bears seasonal fruit and is one of Indonesia's leading export commodity. Mangosteen production in Indonesia is still low and not continuous, because there are several factors that influence it. One of them is the character of biennial bearing in mangosteen one year produce high fruit load followed by a next year of very low production. Therefore it is necessary to induce off season mangosteen flowering. This study aims to determine: (1) the effect of Paklobutrazol on the flowering of mangosteen plants, (2) the effect of adding KNO3 and Etefon on the acceleration of mangosteen flowering. This research was conducted in Mulangmaya Village, Kota Agung Timur District, Tanggamus, Lampung. Regency at an altitude of 250 m above sea level from September 2018 to April 2019. This research used a Randomized Block Design (RBD) with a single factor consisting of 3 treatments, namely P1 ( manure 10 kg/plant + NPK Nitrophonska 1 kg/plant, P2 (Paclobutrazol 2 ml/l + KNO3 20 g/l + manure 10 kg/plant + NPK Nitrophonska 1 kg/plant), and P3 (Paclobutrazol 2 ml/l + Etefon 40 ml/l + manure 10 kg/plant + NPK Nitrophonska 1 kg/plant). The data obtained were analyzed by analysis of variance and the mean separation was carried out by orthogonal contrast test at the 5% significance level. The results showed that the treatment of P2 (Paclobutrazol 2 ml/l + KNO3 20 g/l + manure 10 kg/plant + NPK Nitrophonska 1 kg/plant) on mangosteen plants was able to spur flowering faster with a difference of 12 days (8.70% ), and increased the total number of fruits per plant by a difference of 41 fruit (38.80%). The P3 treatment (Paclobutrazol 2 ml/l + Etefon 40 ml/l + manure 10 kg/plant + NPK Nitrophonska 1 kg/plant), unexpectedly causing significant leaf drop 3 days after Ethephon spray, and new leaves were formed a month later. Keywords : Ethephon, KNO3, Paclobutrazol, and mangosteen flowering

Effect of Irrigation Water pH on the Performance of Healthy and Huanglongbing-affected Citrus

Huanglongbing [HLB (Candidatus Liberibacter asiaticus)] is one of the most devastating diseases in citrus (Citrus sp.). Field observations in Florida have shown that citrus groves with high soil and irrigation water pH decline rapidly under HLB-prevalent conditions. It is worth noting that irrigation water pH has always been high in Florida; however, neither tree decline nor low productivity under such conditions has been an issue for citrus before HLB. Therefore, there is a need to determine if HLB increases citrus tree sensitivity to high-pH irrigation water. The objective of this research was to evaluate the molecular and physiological responses of healthy and HLB-affected citrus trees irrigated with water at pH levels of 5.8, 7.0, and 8.0. The results demonstrated that soil pH is positively correlated with irrigation water pH. Overall, regardless of disease occurrence, tree performance decreased as pH increased. HLB-affected trees at pH 8.0 had the greatest mortality (40%) and leaf drop (87%) and the lowest height growth (<1%) and leaf biomass (0.1 g). In contrast, HLB-affected trees at pH 5.8 had the lowest mortality (0%) and leaf drop (16%) and the greatest height growth (6.6%) and leaf biomass (5.5 g). Growth and survival data indicate that high pH had a less negative impact on healthy trees than HLB-affected trees, and that HLB symptoms were exacerbated at pH 8.0 compared with pH 5.8. A transcriptomic analysis of root tissue conducted at the end of the experiment further suggested that HLB-affected trees at pH 5.8 were actively detoxing stress-induced radicals and had increased growth and developmental processes with the downregulation of jasmonic acid biosynthesis compared with healthy trees. This implies that at pH 5.8, HLB-affected trees were under less stress than healthy trees. Compared with healthy trees, HLB-affected trees at pH 8.0 resulted in upregulated immune system processes, defense responses, and cell death; no processes were significantly downregulated in HLB-affected trees compared with healthy trees at pH 8.0. Physiological and molecular observations suggest an interaction between HLB and irrigation water pH whereby HLB symptoms are exacerbated in response to high irrigation water pH.

The Effect of Marigold Leaves (Tagetes Erecta) Extract to Aedes Sp.Mosquito Mortality for the Biology Learning Source of Module Form

Background: Indonesia is rich in plants, one of which is leaf drop shit (Tagetes erecta) which has the potential as a vegetable insecticide. Diverse local plants will be very good if integrated in learning through modules so that they can help preserve local plants. The objectives of this study are: (1) to determine the effect of Tahitian Kotok (T. erecta) leaf extract on the mortality of Aedes sp. Mosquitoes. (2) determine the concentration of leaf extract of Tahitian Kotok (T. erecta) which can influence the mortality of Aedes sp. (3) compile teaching materials in the form of modules. Methods: This research is an experiment that is giving treatment and observation of Aedes sp. with 3 extractions of Kotok Tahi (T. erecta) leaves and 1 control treatment. The study was conducted with 4 replications, each: treatment 1 (0.5%), treatment 2 (1.3%), and treatment 3 (2%). The results of experimental research are then used as a basis for making modules and their feasibility tested. Results: Based on the research data there is a very significant effect on mortality resulting from each given extraction concentration. Based on research at a concentration of 2%, the highest mortality effect from Aedes sp. that is, with an average of 92.5% with 37 deaths from 40 mosquitoes. Kotok (T erecta) leaf extraction can be used as an alternative in controlling Aedes sp. Conclusion: The results of the study can be used as learning resources in the form of modules and are feasible to use with the validation results of 85.2%.