scholarly journals Distribution pattern of developmental stages of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) on the surface of citrus leaves

2020 ◽  
Vol 1 (89) ◽  
pp. 1-6
Author(s):  
Meriem Dahmane ◽  
Gahdab Chakali
Keyword(s):  
Developmental Stages ◽  
Leaf Surface ◽  
Leaf Age ◽  
Pupal Stage ◽  
Phyllocnistis Citrella ◽  
Citrus Leafminer ◽  
Leaf Surfaces ◽  
Young Leaves ◽  
Citrus Orchards ◽  
Citrus Leaves

The leafminer Phyllocnistis citrella (Stainton, 1856) (Lepidoptera: Gracillariidae), is considered a potential serious pest of citrus in Algeria. The aim of this work was to investigate the relationship between the ecophases of the citrus leafminer and the leaf surface of the Washington navel citrus variety. Practically all the examined leaves of the young shoots were occupied by at least a developmental stage of this insect. More than 80% of the leafminer ecophases were distributed on the lower surfaces of the leaves. A relationship is highlighted between the leaf surfaces and the stages evolution of citrus leafminer. The choice of area laying by females is decisive for the survival and evolution of stages of development of the insect in relationship with leaf age. The analysis of the eggs distribution revealed that young leaves, with leaf surface smaller than 2 cm², were significantly preferred by females for oviposition. However, the larvae were abundant on leaf surfaces smaller than 6 cm² which provide a favorable environment for the development of larvae in order to realize their respective gallery. The pupal stage was observed almost uniformly on all the analyzed area classes. These results could contribute to the guidelines for pest risk assessment highlighting the intervention for the protection of citrus orchards against heavy infestations of Phyllocnistis citrella.

scholarly journals Urea Nitrogen Uptake by Citrus Leaves

HortScience ◽  
2001 ◽  
Vol 36 (6) ◽  
pp. 1061-1065 ◽  
Author(s):  
B.R. Bondada ◽  
J.P. Syvertsen ◽  
L.G. Albrigo
Keyword(s):  
Leaf Age ◽  
Extended Period ◽  
Field Studies ◽  
Urea Nitrogen ◽  
N Source ◽  
Leaf Surfaces ◽  
Young Leaves ◽  
Leaf N Concentration ◽  
Citrus Leaves ◽  
Leaf N

Foliar-applied urea nitrogen (N) has potential to become an important component in fertilizer programs for citrus in Florida and other citrus growing areas as it can reduce nitrate leaching into ground water. We evaluated seasonal absorption characteristics of three urea formulations, Triazone-urea, liquid urea, and spray grade urea by citrus leaves that were from 2 weeks to 6 months old. The effect of leaf age on 15N absorption by N-deficient and N-sufficient leaves, together with urea absorption over an eight-week period were studied using greenhouse-grown and field-grown plants. All foliar N applications were based on a recommended rate of 34 kg N/ha in 469 L of water. In the field studies, leaf N was increased similarly by the three urea formulations one week after three weekly applications. Young leaves (0.25 month and 1 month old) absorbed a greater percentage of N than the older leaves (3 month and 6 month old). Epicuticular wax concentration increased and 15N absorption declined with leaf age. Nitrogen deficient leaves (1.80% N) had greater wax concentration and lower N absorption than N sufficient leaves (2.60% N). Four to 8 weeks after urea applications, Triazone-urea sprayed leaves had significantly greater leaf N concentration than leaves sprayed with liquid urea or nonsprayed control leaves. The greenhouse studies revealed that the 15N absorption was greater through abaxial leaf surfaces than through adaxial surfaces regardless of leaf N level and application time. Applying foliar 15N-urea during night (2000 hr to 2200 hr) resulted in greater absorption of 15N than in the morning (0800 hr to 1000 hr) or afternoon (1200 hr to 1400 hr). It is clear that maximum N absorption from foliar urea sprays occurred at night through the abaxial surfaces of young leaves with sufficient N. Triazone-urea acted as a slow-release N source that could be exploited in supplying N over an extended period of time.

scholarly journals Anatomical and Histochemical Effects of Feeding by Citrus Leafminer Larvae (Phyllocnistis citrella Stainton) in Citrus Leaves

1997 ◽  
Vol 122 (6) ◽  
pp. 829-836 ◽  
Author(s):  
D.S. Achor ◽  
H. Browning ◽  
L.G. Albrigo
Keyword(s):  
Callus Tissue ◽  
Light And Electron Microscopy ◽  
Outer Cell ◽  
Phyllocnistis Citrella ◽  
Microbial Invasion ◽  
Citrus Leafminer ◽  
Wound Recovery ◽  
Citrus Leaves ◽  
Tissue Recovery ◽  
Outer Cell Wall

Young expanding leaves of `Ambersweet' [Citrus reticulata Blanco × C. paradisi Macf. × C. reticulata) × C. sinensis (L) Osb.] with feeding injury by third larval stage of citrus leafminer (Phyllocnistis citrella) were examined by light and electron microscopy for extent of injury and tissue recovery over time. Results confirmed that injury is confined to the epidermal layer, leaving a thin covering over the mine tunnel that consisted of the cuticle and outer cell wall. Wound recovery consisted of two possible responses: the production of callus tissue or the formation of wound periderm. The production of callus tissue developed within 3 days of injury when the uninjured palisade or spongy parenchyma below the injured epidermis produced callus tissue through periclinal or diagonal cell divisions. After 1 month, the entire epidermis was replaced by callus tissue. In the absence of secondary microbial invasion, this callus tissue developed a thick cuticle, followed by development of a covering of platelet wax after 4 months. Alternatively, wound periderm formed if the outer cuticular covering was torn before the cuticle had developed sufficiently to prevent the exposed cells from being desiccated or invaded by fungi, bacteria, or other insects. The wound periderm consisted of a lignified layer of collapsed callus cells, a suberized phellem layer, and a multilayered phelloderm-phellogen. Since there were always cellular collapse or fungi and bacteria associated with wound periderm formation, it was determined to be a secondary effect, not a direct effect of leafminer feeding.

Distribution of Trialeurodes vaporariorum and Bemisia tabaci (Homoptera: Aleyrodidae) on Some Greenhouse-grown Ornamental Plants

1993 ◽  
Vol 28 (1) ◽  
pp. 102-112 ◽  
Author(s):  
Tong-Xian Liu ◽  
Ronald D. Oetting ◽  
G. David Buntin
Keyword(s):  
Bemisia Tabaci ◽  
Developmental Stages ◽  
Ornamental Plants ◽  
Leaf Age ◽  
Trialeurodes Vaporariorum ◽  
Middle Aged ◽  
Greenhouse Whitefly ◽  
Whole Plant ◽  
Young Leaves ◽  
The Vertical Distribution

The within-plant and between-plant distributions of all stages of both greenhouse whitefly (GHWF), Trialeurodes vaporariorum (Westwood) on poinsettia, chrysanthemum and gerbera daisy, and sweetpotato whitefly (SPWF), Bemisia tabaci (Gennadius) on poinsettia, were examined using Taylor's power law (s2 = amb) and Iwao's patchiness () methods. We found that all developmental stages of the two whitefly species on all plants examined were aggregated within and between plants. The vertical distribution of whitefly stages is stratified among leaves within the plant with respect to leaf age rather than relative height of the leaves on the plants. Most of the adults, eggs and the first-instar nymphs occurred on young leaves. The second- and third-instar nymphs occurred on middle-aged leaves, and most of the pupae and empty pupal cases occurred on middle-aged and older leaves. Comparison of whitefly counts from the different combinations of top, middle, and bottom leaves with the whole-plant counts on poinsettia was correlated and these leaves can be sampled as an indication of population levels within a greenhouse population.

scholarly journals Comparison of mineral spray oil, Confidor, Dursban, and Abamectin used for the control of Phyllocnistis citrella (Lepidoptera: Gracillaridae), and an evaluation of the activity of this pest in citrus orchards in northern Iran

2014 ◽  
Vol 54 (2) ◽  
pp. 156-163 ◽  
Author(s):  
Mohammad Reza Damavandian ◽  
Seyedeh Fatemeh Kiaeian Moosavi
Keyword(s):  
Broad Spectrum ◽  
Northern Iran ◽  
Phyllocnistis Citrella ◽  
Damage Reduction ◽  
Citrus Leafminer ◽  
Comparison Results ◽  
Significant Damage ◽  
Citrus Orchards ◽  
Synthetic Pesticides ◽  
Live Larva

Abstract The efficacy of three types of mineral spray oil (MSO), and Abamectin plus MSO to control the citrus leafminer Phyllocnistis citrella Stainton were compared with the conventional broad spectrum pesticides, Confidor, and Dursban, in two citrus orchards in northern Iran. Differences were found among the various concentrations of MSO in the number of mines and live larva per leaf, sampled 5 days after the application of 3 sprays at an interval of 5 days. Mineral spray oil applied at a rate of ≥ 0.65% in water, showed no significant differences when compared with Confidor, and Dursban. Abamectin plus MSO at a rate of 0.02% plus 0.50% in water respectively, provided the highest level of control and reduced the population of larva up to 85%. Generally, a concentration of ≥ 0.65% MSO in water caused a significant damage reduction. However, by reducing the MSO concentration, the rate of control was decreased. In another field experiment conducted in mature citrus orchards, the effect of two pest management types (applying just MSO vs. usage of synthetic pesticides) on the activity of P. citrella, was evaluated. The comparison results indicated that there is more P. citrella damage in orchards under pressure of synthetic pesticides than in orchards in which the synthetic pesticides were eliminated for years.

scholarly journals Ants affect the infestation levels but not the parasitism of honeydew and non-honeydew producing pests in citrus

2013 ◽  
Vol 104 (4) ◽  
pp. 405-417 ◽  
Author(s):  
A. Calabuig ◽  
F. Garcia-Marí ◽  
A. Pekas
Keyword(s):  
Western Mediterranean ◽  
Arthropod Community ◽  
Phyllocnistis Citrella ◽  
Growing Seasons ◽  
Citrus Leafminer ◽  
Percent Parasitism ◽  
Pheidole Pallidula ◽  
Citrus Orchards ◽  
Exclusion Experiments ◽  
The Impact

AbstractAnts act simultaneously as predators and as hemipteran mutualists, and thereby may affect the composition and population dynamics of a wide arthropod community. We conducted ant-exclusion experiments in order to determine the impact of ants on the infestation levels and parasitism of three of the most important citrus pests of western Mediterranean citrus: the honeydew producer Aleurothrixus floccosus Maskell (woolly whitefly) and the non-honeydew producers Aonidiella aurantii Maskell (California red scale; CRS) and Phyllocnistis citrella (Staiton) (citrus leafminer). The study was conducted in three commercial citrus orchards, each one dominated by one ant species (Pheidole pallidula, Lasius grandis or Linepithema humile) during two consecutive growing seasons (2011 and 2012). We registered a significant reduction of the CRS densities on fruits in the ant-excluded treatment in the three orchards and in the two seasons, ranging from as high as 41% to as low as 21%. Similarly, the percentage of shoots occupied by A. floccosus was significantly lower in the ant-excluded plots in the orchards dominated by P. pallidula and L. humile. No significant differences were registered in the percentage of leaf surface loss caused by P. citrella between ant-allowed and ant-excluded treatments in any case. We found no significant differences in the percent parasitism between ant-allowed and ant-excluded treatments for honeydew and non-honeydew producing herbivores. These results suggest that: (i) ant management should be considered in order to reduce herbivore populations in citrus and (ii) mechanisms other than parasitism (e.g., predation) might explain the differences in herbivore infestation levels between treatments.

scholarly journals Foliar Nitrogen Fertilization of Citrus in Florida

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 773D-773
Author(s):  
B.R. Bondada ◽  
J.P. Syvertsen ◽  
L. Albrigo ◽  
A. Alva ◽  
P. Petracek
Keyword(s):  
Leaf Age ◽  
Contact Angles ◽  
Absorption Efficiency ◽  
Wax Deposition ◽  
Surface Wax ◽  
Young Leaves ◽  
Citrus Production ◽  
Citrus Leaves ◽  
Leaf Wettability ◽  
Cuticle Thickness

Foliar applications of urea nitrogen (N) is a relatively new practice in Florida citrus production resulting from applied research and changes in citrus fertilizer management philosophy. The present study investigated the effect of leaf age and surface morphology on leaf wettability as measured by contact angles, and absorption efficiency of foliar-applied N. Young leaves (0.25 and 1 month) were more efficient than old leaves in the absorption of foliar-applied N. Contact angles of water, urea-, and triazone-N solutions were low in the young leaves. The adaxial surfaces had lower contact angles than abaxial surfaces in each leaf age group. Inefficient N absorption and large contact angles in old leaves (3 and 6 months) were related to surface wax deposition and cuticle thickness, which increased with leaf age. 15N- and 14C-labeled urea are being used to determine precisely how the cuticle and wax affect foliar N absorption in citrus leaves.

scholarly journals Pathogenicity and Side Effect of Indigenous Beauveria bassiana on Coccinella undecimpunctata and Hippodamia variegata (Coleoptera: Coccinellidae)

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 42
Author(s):  
Samy Sayed ◽  
Sayed-Ashraf Elarrnaouty ◽  
Saad AlOtaibi ◽  
Mohamed Salah
Keyword(s):  
Beauveria Bassiana ◽  
Indirect Effect ◽  
Developmental Stages ◽  
Larval Instar ◽  
Pupal Stage ◽  
Tween 80 ◽  
Contact Method ◽  
Coccinella Undecimpunctata ◽  
Hippodamia Variegata ◽  
Application Methods

This study aimed to estimate the virulence of an indigenous Beauveria bassiana on all developmental stages of two indigenous coccinellids; Coccinella undecimpunctata and Hippodamia variegata through three application methods; direct spray, contact method, and feeding on aphids treated with the fungus (ingestion). Also, indirect effect on all developmental stages resulted from 1st larval instar treated with these application methods. All treatments were done with a concentration of 1 × 105 which was recommended in previous studies for different aphid species with a control of 0.02% Tween 80 (v/v). The mortality of 1st larval instar of both H. variegata and C. undecimpunctata and pupal stage of C. undecimpunctata were significantly increased with spray method only. Also, contact method achieved significantly higher mortality on 1st larval instar of C. undecimpunctata only. Regard to indirect effect, except of mortality of 1st larval instar of both predators and 2nd larval instar of H. variegata, other developmental instars/stages of both predators were not affected by B. bassiana through the three tested application methods in the mortality, duration, survival, cumulative survival male and female longevity, and fecundity. Therefore, both tested predatory coccinellids could be compatible with this indigenous isolate of B. bassiana where, in general, there are no negative effects of the fungus on both predators.

scholarly journals Automated Detection of Tetranychus urticae Koch in Citrus Leaves Based on Colour and VIS/NIR Hyperspectral Imaging

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1002
Author(s):  
María Gyomar Gonzalez-Gonzalez ◽  
Jose Blasco ◽  
Sergio Cubero ◽  
Patricia Chueca
Keyword(s):  
Hyperspectral Imaging ◽  
Tetranychus Urticae ◽  
Visual Inspection ◽  
Vision System ◽  
Automated Detection ◽  
Nutritional Deficiencies ◽  
Phyllocnistis Citrella ◽  
Mature Leaves ◽  
Citrus Leaves ◽  
Tetranychus Urticae Koch

Tetranychus urticae Koch is an important citrus pest that produces chlorotic spots on the leaves and scars on the fruit of affected trees. It is detected by visual inspection of the leaves. This work studies the potential of colour and hyperspectral imaging (400–1000 nm) under laboratory conditions as a fast and automatic method to detect the damage caused by this pest. The ability of a traditional vision system to differentiate this pest from others, such as Phyllocnistis citrella, and other leaf problems such as those caused by nutritional deficiencies, has been studied and compared with a more advanced hyperspectral system. To analyse the colour images, discriminant analysis has been used to classify the pixels as belonging to either a damaged or healthy leaves. In contrast, the hyperspectral images have been analysed using PLS DA. The rate of detection of the damage caused by T. urticae with colour images reached 92.5%, while leaves that did not present any damage were all correctly identified. Other problems such as damage by P. citrella were also correctly discriminated from T. urticae. Moreover, hyperspectral imaging allowed damage caused by T. urticae to be discriminated from healthy leaves and to distinguish between recent and mature leaves, which indicates whether it is a recent or an older infestation. Furthermore, good results were achieved in the discrimination between damage caused by T. urticae, P. citrella, and nutritional deficiencies.

scholarly journals The Scent of Ant Brood: Caste Differences in Surface Hydrocarbons of Formica exsecta Pupae

2021 ◽  
Author(s):  
Unni Pulliainen ◽  
Nick Bos ◽  
Patrizia d’Ettorre ◽  
Liselotte Sundström
Keyword(s):  
Surface Chemistry ◽  
Chemical Communication ◽  
Cuticular Hydrocarbons ◽  
Social Insects ◽  
Developmental Stages ◽  
Pupal Stage ◽  
Male And Female ◽  
Chemical Stimuli ◽  
Caste Differences ◽  
Long Chain

AbstractChemical communication is common across all organisms. Insects in particular use predominantly chemical stimuli in assessing their environment and recognizing their social counterparts. One of the chemical stimuli used for recognition in social insects, such as ants, is the suite of long-chain, cuticular hydrocarbons. In addition to providing waterproofing, these surface hydrocarbons serve as a signature mixture, which ants can perceive, and use to distinguish between strangers and colony mates, and to determine caste, sex, and reproductive status of another individual. They can be both environmentally and endogenously acquired. The surface chemistry of adult workers has been studied extensively in ants, yet the pupal stage has rarely been considered. Here we characterized the surface chemistry of pupae of Formica exsecta, and examine differences among sexes, castes (reproductive vs. worker), and types of sample (developing individual vs. cocoon envelope). We found quantitative and qualitative differences among both castes and types of sample, but male and female reproductives did not differ in their surface chemistry. We also found that the pupal surface chemistry was more complex than that of adult workers in this species. These results improve our understanding of the information on which ants base recognition, and highlights the diversity of surface chemistry in social insects across developmental stages.

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