scholarly journals Occurrence, Biology and Harmfulness of Byctiscus betulae (L.) (Coleoptera, Rhynchitidae)

Author(s):  
Jaroslav Urban

In 2012 and 2013, was studied the occurrence, biology and harmfulness ofByctiscus betulae(L.) (Rhynchitidae) on forest woody plants in the Brno region. Leaf rolls were found on 13 species (and 10 genera) of woody plants. Most frequently, they occurred onFagus sylvatica,Tiliaspp. (namely onT. cordata),Salix capreaandPopulus tremula. The beetles hibernate in ground pupal chambers and appear on woody plants in the last decade of April. After hibernation, females live on average seven (males five) weeks, and damage on average 40 (males 25) cm2of leaves. The females create leaf rolls on annual shoots they have gnawed, exceptionally (in 2%) on leaves with damaged petioles. In the rolls onF. sylvatica, they roll on average 5.6 leaves whose total average area is 49.5 cm2and lay on average 5.1 eggs. In the rolls onTiliaspp., they roll on average 3.3 leaves whose total area is 63.2 cm2and lay on average 4.9 eggs. In the rolls onS. caprea, they roll on average 3.3 leaves whose total area is 38.3 cm2and lay on average 3.5 eggs. The maximum number of laid eggs (on average 8.0) was observed in the leaf rolls onVitis vinifera. The average number of eggs in the leaf rolls was decreasing from May to July. The number of eggs was increasing with the increasing total leaf area rolled. The females lay on average 50 eggs. OnP. tremula,S. capreaandPyrus pyrasterthey create about 15 leaf rolls, onF. sylvaticaandTiliaspp. about 10 leaf rolls and onV. viniferaca. 8 leaf rolls. Embryogenesis lasts from 8 to 9 days. Larvae develop over 3 instars and damage ca. 300 mm2of leaves. Coming of age within 4−7 weeks, they leave the leaf rolls from mid-June to the beginning of September.

1996 ◽  
Vol 10 (4) ◽  
pp. 951-956 ◽  
Author(s):  
Muhammad A. Bhatti ◽  
Kassim Al-Khatib ◽  
Robert Parker

‘Lemberger’ wine grape response was evaluated when chlorsulfuron, tribenuron, thifensulfuron, chlorsulfuron plus metsulfuron, thifensulfuron plus tribenuron, and 2,4-D were applied up to three times at weekly intervals in 1992 and 1993 at rates simulating drift. All herbicides injured grapevines visibly. Symptoms increased and total leaf area and grape pruning weight decreased as the herbicide rate and number of applications increased. Grapevines generally recovered within 45 to 60 d from symptoms caused by single exposures to low levels of sulfonylurea herbicides. Multiple exposures of grapevines to 2,4-D, tribenuron, and chlorsulfuron plus metsulfuron at 1/100 of the maximum use rate for wheat caused the greatest injury, which persisted throughout the entire growing season and reduced pruning weight. Based on potential use rate, the order of herbicide phytotoxicity was 2,4-D > tribenuron > chlorsulfuron plus metsulfuron > thifensulfuron plus tribenuron > chlorsulfuron > thifensulfuron. Rates that slightly injured grapevines did not reduce growth as measured by pruning weight. However, multiple exposure to high rates of 2,4-D, tribenuron, and chlorsulfuron plus metsulfuron adversely affected growth.


HortScience ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 696-698 ◽  
Author(s):  
F.J. Montero ◽  
J.A. de Juan ◽  
A. Cuesta ◽  
A. Brasa

The importance of rapid, nondestructive, and accurate measurements of leaf area (LA) in agronomic and physiological studies is well known, but a search of the literature revealed little information available for grape (Vitis vinifera L.). The results described herein include a comparison of 12 different mathematical models for estimating leaf area in `Cencibel'. The simplest, most accurate regression equations were: LAi = 0.587 LW (R2 = 0.987) and LAi = 0.588 LW (R2 = 0.994), where LAi is leaf area measured using image analysis and LW is leaf length × maximum width. Use of maximum width (W), leaf length (L), petiole length (Lp), and dry weight of leaves (DML) as single variables in the regression equations were not as closely associated with total leaf area, although their R2 values were also highly significant.


1974 ◽  
Vol 63 (3) ◽  
pp. 431-440
Author(s):  
D. M. Benjamin ◽  
W. M. Demba

AbstractAdults of two subspecies of Entypotrachelus meyeri Kolbe defoliate tea established on land cleared of montane rain forest, E. m. meyeri Kolbe occuring in Kenya and Tanzania to the west of the Great Rift Valley and E. m. micans Hust. only in the foothills of Mt. Kenya east of the Rift. Both subspecies are polyphagous and the host-plants are listed. Oviposition by E. m. meyeri occurs throughout the year; eggs hatch in 10–29 days, and the larvae feed on the roots of tea and various woody plants. The adults cannot fly, but field observations showed they could disperse 2–23 m in 14 days; mark-recapture data showed that 50% of the females lived 32 days, and males 37 days. The bionomics of E. m. micans were similar, but adults lived longer (50% of the females lived 55 days, males 49 days). The leaf area consumed by adults of E. m. micans was 66 mm2/day whereas the total leaf area of a seedling is 30–50 cm2, and it is shown that three adults per plant could effect defoliation in 21 days, assuming no new leaves are formed; leaf destruction at this rate is not considered economically important. Larvae of E. m. micans caused 37% rejection of tea seedlings through destruction of the tap root.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yinli Bi ◽  
Huili Zhou

AbstractA well-developed canopy structure can increase the biomass accumulation and yield of crops. Peanut seeds were sown in a soil inoculated with an arbuscular mycorrhizal fungus (AMF) and uninoculated controls were also sown. Canopy structure was monitored using a 3-D laser scanner and photosynthetic characteristics with an LI-6400 XT photosynthesis system after 30, 45 and 70 days of growth to explore the effects of the AMF on growth, canopy structure and photosynthetic characteristics and yield. The AMF colonized the roots and AMF inoculation significantly increased the height, canopy width and total leaf area of the host plants and improved canopy structure. AMF reduced the tiller angle of the upper and middle canopy layers, increased that of the lower layer, reduced the leaf inclination of the upper, middle and lower layers, and increased the average leaf area and leaf area index after 45 days of growth, producing a well-developed and hierarchical canopy. Moreover, AMF inoculation increased the net photosynthetic rate in the upper, middle and lower layers. Plant height, canopy width, and total leaf area were positively correlated with net photosynthetic rate, and the inclination angle and tiller angle of the upper leaves were negatively correlated with net photosynthetic rate. Overall, the results demonstrate the effects of AMF inoculation on plant canopy structure and net photosynthetic rate.


1956 ◽  
Vol 7 (2) ◽  
pp. 98 ◽  
Author(s):  
JN Black

Changes in the pre-emergence distribution of dry matter in subterranean clover (Trifolium subterraneum L.) variety Bacchus Marsh were followed at 21°C, using three sizes of seed and three depths of sowing, ½, 1¼, and 2 in. Decreasing seed size and increasing depth of sowing both reduce the weight of the cotyledons a t emergence. Seed of the three sizes were sown a t three depths in pot culture a t staggered intervals so that emergence was simultaneous. Dry weight in the early vegetative stage was proportional to seed size, and total leaf area and leaf numbers showed similar trends. Plants of each seed size grew at the same relative rate. No effect of depth of sowing could be detected, and this was shown to be due to the cotyledon area a t emergence being constant for any given seed size, regardless of varying depth of sowing and hence of cotyledon weight. It was concluded that seed size in a plant having epigeal germination and without endosperm is of importance: firstly, in limiting the maximum hypocotyl elongation and hence depth of sowing, and secondly, in determining cotyledon area. Cotyledon area in turn influences seedling growth, which is not affected by cotyledon weight. Once emergence has taken place, cotyledonary reserves are of no further significance in the growth of the plants.


2009 ◽  
Vol 23 (1) ◽  
pp. 130-135 ◽  
Author(s):  
André Mantovani ◽  
Ricardo Rios Iglesias

The amount of resources invested in reproduction is closely correlated to plant size. However, the increase in reproductive investment is not always proportional to the increase in vegetative growth, as the proportion of plant resources allocated to reproduction can increase, decrease or be maintained along different plant sizes. Although comprising thousand of species, epiphytes are poorly studied in relation to reproductive allocation (RA). We describe the variation in the RA of the epiphytic bromeliad Tillandsia stricta Soland with increasing plant sizes. Our goal is not only to evaluate the RA of the whole inflorescence but also quantify the contribution of ancillary structures in the final RA of this plant species. With increasing sizes of T. stricta the reproductive allocation of biomass to the whole inflorescence decreased significantly along plant sizes from 37% to 12%. Reproductive allocation to ancillary and to flowers decreased respectively from 30% to 9% and 10% to 3%. As leaves are the main source of water and nutrients absorption in atmospheric Tillandsia, the total leaf area and area per leaf were used as indicators of foraging capacity, that also increased with plant size. We discuss these results with respect to the capacity of T. stricta to reproduce in the heterogeneous environment of the canopies.


2021 ◽  
Vol 22 (10) ◽  
Author(s):  
Benyamin Lakitan ◽  
Kartika Kartika ◽  
Laily Ilman Widuri ◽  
Erna Siaga ◽  
Lya Nailatul Fadilah

Abstract. Lakitan B, Kartika K, Widuri LI, Siaga E, Fadilah LN. 2021. Lesser-known ethnic leafy vegetables Talinum paniculatum grown at tropical ecosystem: Morphological traits and non-destructive estimation of total leaf area per branch. Biodiversitas 22: 4487-4495. Talinum paniculatum known as Java ginseng is an ethnic vegetable in Indonesia that has also been utilized as a medical plant. Young leaves are the primary economic part of T. paniculatum, which can be eaten fresh or cooked. This study was focused on characterizing morphological traits of T. panicultaum and developing a non-destructive yet accurate and reliable model for predicting total area per leaf cluster on each elongated branch per flush growth cycle. The non-destructive approach allows frequent and timely measurements. In addition, the developed model can be used as guidance for deciding the time to harvest for optimum yield. Results indicated that T. paniculatum flourished rapidly under wet tropical conditions, especially if they were propagated using stem cuttings. The plants produced more than 50 branches and more than 800 leaves, or on average produced more than 15 leaves per branch at the age of nine weeks after planting (WAP). The zero-intercept linear model using a combination of two traits of length x width (LW) as a predictor was accurate and reliable for predicting a single leaf area (R2 = 0.997). Meanwhile, the estimation of total area per leaf cluster was more accurate if three traits, i.e., number of leaves, the longest leaf, and the widest leaf in each cluster were used as predictors with the zero-intercept linear regression model (R2 = 0.984). However, the use of a single trait of length (L) and width (W) of the largest leaf within each cluster as a predictor in the power regression model exhibited moderately accurate prediction at the R2 = 0.883 and 0.724, respectively.


Author(s):  
Jaroslav Urban

The paper deals with the occurrence, development and harmfulness of Deporaus betulae (L.). The majority of field studies was carried out at Training Forest Enterprise (TFE) Masaryk Forest in Křtiny (District Brno-venkov) in 2010 and 2011. In addition to this, the species was studied in detail also in a laboratory. It occurred mostly on Betula pendula and Carpinus betulus. Rarely, the species was found on Alnus glutinosa and Corylus avellana and only sporadically on Fagus sylvatica, Quercus petraea, Tilia cordata and T. platyphyllos. In the studied area, larvae and pupae hibernate. Beetles occur on trees from the end of April to the beginning of July, sporadically later. Females lay on average 2.5 (in the laboratory 4.4) eggs into rolls on B. pendula, on C. betulus 2.2 eggs. During two months, they damage on average 5.3 cm2 leaves creating 14 rolls and laying 35 eggs into the rolls. Larvae consume only 1.7 cm2 leaf blade. The development of the species takes three to four months from egg laying to the departure of larvae into soil. On leaves of B. pendula of an average area of 14.2 cm2, females roll up the same area (about 11.2 cm2) as on leaves of C. betulus of an area of 21.7 cm2. Into the rolls, they lay on average the same number of eggs. The average number of eggs in rolls increases with the increased area of B. pendula leaf blade. Trees partly compensate for the reduction of assimilatory area also by the growth of the area of neighbouring undamaged leaves (on average by 12.7 %).


Genetika ◽  
2003 ◽  
Vol 35 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Nada Hladni ◽  
Dragan Skoric ◽  
Marija Kraljevic-Balalic

The main goals of sunflower breeding in Yugoslavia and abroad are increased seed yield and oil content per unit area and increased resistance to diseases, insects and stress conditions via an optimization of plant architecture. In order to determine the mode of inheritance, gene effects and correlations of total leaf number per plant, total leaf area and plant height, six genetically divergent inbred lines of sunflower were subjected to half diallel crosses. Significant differences in mean values of all the traits were found in the F1 and F2 generations. Additive gene effects were more important in the inheritance of total leaf number per plant and plant height, while in the case of total leaf area per plant the nonadditive ones were more important looking at all the combinations in the F1 and F2 generations. The average degree of dominance (Hi/D)1/2 was lower than one for total leaf number per plant and plant height, so the mode of inheritance was partial dominance, while with total leaf area the value was higher than one, indicating super dominance as the mode of inheritance. Significant positive correlation was found: between total leaf area per plant and total leaf number per plant (0.285*) and plant height (0.278*). The results of the study are of importance for further sunflower breeding work.


Sign in / Sign up

Export Citation Format

Share Document