plant damage
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2021 ◽  
Vol 104 (4) ◽  
pp. 213-217
Author(s):  
E. L. Gasich ◽  
A. S. Orina*

Fungal strain MF KP-12.1, which is similar in morphological and cultural characteristics to Botryosphaeria fungi, was isolated from the seeds of white lupine variety Dega grown in Oryol region in 2018. Phylogenetic analysis of the large rRNA subunit (LSU), elongation factor-1α (TEF) and internal transcribed spacer (ITS) fragments was used to accurately identify the isolated strain as B. sinensis. When 2-week-old white lupine plants were treated under laboratory conditions with mycelial suspension of B. sinensis MF KP-12.1, plant damage reached 67 % on day 3, and 100 % plant death was observed on day 10. Pathogenicity of B. sinensis MF KP-12.1 was confirmed by re-isolation of the strain from damaged plant tissue. This is the first detection of B. sinensis on white lupine, which has not been previously reported as a host for this fungus. It is also the first detection of B. sinensis in Russia.


Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1129
Author(s):  
Sulav Paudel ◽  
Pragya Kandel ◽  
Dependra Bhatta ◽  
Vinod Pandit ◽  
Gary W. Felton ◽  
...  

Elevation gradients are used as a proxy to simulate climate change effects. A field study was conducted along an elevational gradient in Nepal to understand the effects of abiotic conditions on agriculturally important insect herbivore populations (tobacco caterpillar: Spodoptera litura, tomato fruit worm: Helicoverpa armigera, and South American leaf miner, Tuta absoluta) and herbivory damage on tomatoes. Elevation ranged from 100 m to 1400 m above sea level, representing different climatic zones where tomatoes are grown. Contrary to our hypothesis, natural herbivore populations and herbivory damage significantly increased at higher elevations. Individual insect species responses were variable. Populations of S. litura and T. absoluta increased at higher elevations, whereas the H. armigera population was highest at the mid-elevational range. Temperature variations with elevation also affected insect catch numbers and the level of plant damage from herbivory. In the context of climate warming, our results demonstrate that the interactive effects of elevation and climatic factors (e.g., temperature) will play an important role in determining the changes in insect pest populations and the extent of crop losses.


Zootaxa ◽  
2021 ◽  
Vol 5060 (4) ◽  
pp. 515-532
Author(s):  
GILLIAN W. WATSON

The checklist of scale insect species recorded from Kenya comprises 14 families, 128 genera and 304 species, of which 207 (68.0%) are probably of African origin, 91 (29.9%) have been introduced from outside Africa and six (2.0%) are of unknown origin. Out of the 207 African species, only 11 (5.3%) have been recorded damaging plants, whereas out of the 91 introduced species, 45 (49.5%) have caused or are highly likely to cause plant damage in Kenya. The most economically important scale insect families in Kenya are (in order of importance) the Pseudococcidae, Coccidae and Diaspididae. Four new combinations are made: Eurycoccus glomerulus De Lotto is transferred to Trionymus, as Trionymus glomerulus (De Lotto) comb. n.; Trionymus sativus James is transferred to Paracoccus, as Paracoccus sativus (James) comb. n.; Pseudococcus masakensis James is transferred to Nipaecoccus as Nipaecoccus masakensis (James) comb. n., and Spilococcus commiphorae De Lotto is transferred to Paracoccus, as Paracoccus commiphorae (De Lotto) comb. n.  


2021 ◽  
Vol 17 ◽  
Author(s):  
Kati Hewitt ◽  
Cory Matthew ◽  
Catherine McKenzie ◽  
Wade Mace ◽  
Alison Popay

The literature on the importance of Epichloë grass endophytes during pasture renewal is reviewed. Perennial ryegrass endophyte strains such as AR1, NEA2, and Standard Endophyte (SE) as well as tall fescue and meadow fescue endophytes, significantly increase seedling survival at establishment under insect pressure, for example from adult Argentine stem weevil, grass grub, and African black beetle. However, in endophyte-infected ryegrass, insect-derived plant damage increases 10–43 days after sowing despite the presence of endophyte. Insecticidal seed treatments can mitigate the vulnerability to insect predation during this time.


Author(s):  
Peter A. Henderson

Comparative surveys of species richness for some animal groups can be undertaken by surveying signs or products such as footprints, faeces, nests, burrows, or cast skins. Measures of the size of populations based on the magnitude of their products or effects are often referred to as population indices. Methods based on the collection of insect exuviae and frass are described and their efficiency discussed. Vertebrate monitoring based on a variety of signs is described. Methods that use plant damage criteria to assess insect herbivore abundance are presented. Methods to determine the relationship between plant damage and insect abundance are described.


Author(s):  
Stefan Toepfer ◽  
Patrick Fallet ◽  
Joelle Kajuga ◽  
Didace Bazagwira ◽  
Ishimwe Primitive Mukundwa ◽  
...  

AbstractThe fall armyworm (Spodoptera frugiperda, Lepidoptera: Noctuidae), which is native to the Americas, has recently invaded Africa and Asia. There, it has become a major pest of maize (Zea mays). The variety of methods used to assess feeding damage caused by its caterpillars makes it difficult to compare studies. In this paper, we aim at determining which leaf damage rating scales for fall armyworm are most consistently used for which purposes, might provide most possibilities for statistical analyses, and would be an acceptable compromise between detail and workload. We first conducted a literature review and then validated the most common scales under field and laboratory conditions. Common leaf damage scales are the nominal “yes-no damage scale” that only assesses damage incidence, as well as difficult-to-analyse ordinal scales which combine incidence and severity information such as the “Simple 1 to 5 whole plant damage scale”, “Davis’ 0 to 9 whorl & furl damage scale”, or “Williams’ 0 to 9 whole plant damage scale”. These scales have been adapted many times, are sometimes used incorrectly, or were wrongly cited. We therefore propose simplifications of some of these scales as well as a novel “0.0 to 4.0 fall armyworm leaf damage index” which improves precision and possibilities for parametric data analyses. We argue that the choice of a scale to use should depend on the desired level of detail, type of data analyses envisioned, and manageable time investment.


Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 198
Author(s):  
Yinping Li ◽  
George N. Mbata ◽  
Somashekhar Punnuri ◽  
Alvin M. Simmons ◽  
David I. Shapiro-Ilan

Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is among the most economically important insect pests of various vegetable crops in the Southern United States. This insect is considered a complex of at least 40 morphologically indistinguishable cryptic species. Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) was initially introduced in the United States around 1985 and has since rapidly spread across the Southern United States to Texas, Arizona, and California, where extreme field outbreaks have occurred on vegetable and other crops. This pest creates extensive plant damage through direct feeding on vegetables, secreting honeydew, causing plant physiological disorders, and vectoring plant viruses. The direct and indirect plant damage in vegetable crops has resulted in enormous economic losses in the Southern United States, especially in Florida, Georgia, and Texas. Effective management of B. tabaci on vegetables relies mainly on the utilization of chemical insecticides, particularly neonicotinoids. However, B. tabaci has developed considerable resistance to most insecticides. Therefore, alternative integrated pest management (IPM) strategies are required, such as cultural control by manipulation of production practices, resistant vegetable varieties, and biological control using a suite of natural enemies for the management of the pest.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 392
Author(s):  
Xavier Chiriboga Morales ◽  
Amanuel Tamiru ◽  
Islam S. Sobhy ◽  
Toby J. A. Bruce ◽  
Charles A. O. Midega ◽  
...  

The fall armyworm (FAW) has recently invaded and become an important pest of maize in Africa causing yield losses reaching up to a third of maize annual production. The present study evaluated different aspects of resistance of six maize cultivars, cropped by farmers in Kenya, to FAW larvae feeding under laboratory and field conditions. We assessed the arrestment and feeding of FAW neonate larvae in no-choice and choice experiments, development of larvae-pupae, food assimilation under laboratory conditions and plant damage in a field experiment. We did not find complete resistance to FAW feeding in the evaluated maize cultivars, but we detected differences in acceptance and preference when FAW larvae were given a choice between certain cultivars. Moreover, the smallest pupal weight and the lowest growth index were found on ’SC Duma 43′ leaves, which suggests an effect of antibiosis of this maize hybrid against FAW larvae. In contrast, the highest growth index was recorded on ‘Rachar’ and the greatest pupal weight was found on ‘Nyamula’ and ‘Rachar’. The density of trichomes on the leaves of these maize cultivars seems not to be directly related to the preference of neonates for feeding. Plant damage scores were not statistically different between cultivars in the field neither under natural nor artificial infestation. However, plant damage scores in ‘Nyamula’ and ‘Jowi’ tended to be lower in the two last samplings of the season compared to the two initial samplings under artificial infestation. Our study provides insight into FAW larval preferences and performance on some African maize cultivars, showing that there are differences between cultivars in these variables; but high levels of resistance to larvae feeding were not found.


2021 ◽  
Vol 37 ◽  
pp. 00166
Author(s):  
Farit Shaikhutdinov ◽  
Igor Serzhanov ◽  
Razil Garayev ◽  
Albina Serzhanova

The article is devoted to the question of the influence of various agro-technological methods on the development of diseases, pests, as well as on the lodging of spring wheat. Over the years of research (2019–2020) on spring wheat crops, the effect of calculated doses of fertilizers at different rates of sowing seeds on plant damage by latent pests and leaf rust damage, as well as the resistance of spring wheat plants to lodging was studied. On the basis of the results obtained, it was possible to establish that at strongly reduced seeding rates, regardless of the nutritional background, the number of damaged plants by the fruit fly, as well as damage by leaf rust, increased sharply. At the same time, excessive thickening of crops did not contribute to a significant further decrease in damage and susceptibility, as well as to lodging of plants.


2021 ◽  
pp. 251-271
Author(s):  
Shou-Hua Wang

Abstract This chapter is intended to illustrate the process of diagnosing insect and mite damage with an emphasis on microscopic insects (such as leaf miners belonging primarily to Lepidoptera, Hymenoptera and Diptera, Phorodon cannabis, Aleyrodidae, Thripidae and stem borers) and mites (including Aculops cannibicola and Tetranychidae), as well as the hidden symptoms caused by them. Diagnosing an insect problem is different from insect identification. A hemp problem should be diagnosed as a type of insect damage first before any taxonomic identification of a suspected insect is performed. That said, growers can make a preliminary diagnosis based on insect population trends in the field and levels of plant damage observed, collect insect specimens of all available stages and submit them to a plant clinic for identification. The chapter also discussed arthropod pest management by preventing pest entry to indoor facilities, monitoring pests throughout production, planting barrier crops, eliminating alternative host plants for pests, trapping flying insects, use of natural enemies and applying alternative products.


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