Number Of Caterpillars Research Articles

Some features of the bioecology of the apple moth <i>Cydia pomonella</i> L. in the conditions of the Moscow region

Relevance. Cydia pomonella L. (Lepidoptera: Tortricidae) is a dominant pest that annually causes significant damage to apple crops. Without a detailed study of the bioecological features of the development of the phytophage in specific study areas, which have undergone noticeable changes under the influence of global warming, it is impossible to build an effective protection system and ensure their environmental safety.Methods. The object of research is C. pomonella. When studying the age gradation and timing of the presence of caterpillars in fallen fruits, conventional and original methods were used; the width of the caterpillar head capsule was measured under an MBS-10 stereoscopic microscope using eyepieces with microscopic rulers. The study of the influence of the photoperiod on the behavior of C. pomonella under short day conditions was carried out in the laboratory in special containers, under natural light and at room temperature (about 21 °C).Results. Studies have shown that not all C. pomonella caterpillars leave fallen fruits within a maximum of one day. After three days of selection and analysis of fallen damaged fruits, caterpillars were found in 34.6–35.5% of them: 18.3–28.3% – age V, 18.3–30.2% – age IV, 28.3–47.9% – III age, 13.2–14.1% – II age, 1.4% – I age. In the laboratory, under short day conditions, according to the years of research, during October – November, 20–21.4% of butterflies flew out of the number of caterpillars of the last age that did not have time to form cocoons in the field.

Acalypha ostryifolia: a natural refuge for Chloridea virescens and Helicoverpa zea (Lepidoptera: Noctuidae) in the Southern United States

Abstract The tobacco budworm, Chloridea virescens (F.), and corn earworm, Helicoverpa zea (Boddie) (heliothines), have had a long-intertwined relationship with respect to their importance as pests in agricultural production systems. Previous studies have examined the impacts of early-season wild host plants on local population density and distribution of these 2 insects on cultivated crops such as cotton, Gossypium hirsutum L., and soybean, Glycine max L. Additional studies have examined the importance of wild host plants, which act as a refuge of nonexposed populations of C. virescens and H. zea to insecticidal toxins from the soil bacterium, Bacillus thuringiensis (Bt) Berliner. The current study examined hophornbeam copperleaf, Acalypha ostryifolia Riddell, as a host plant for mid-late season populations of C. virescens and H. zea. Patches of A. ostryifolia were sampled along roadsides and the edges of fields from 2014 to 2020 in Mississippi, USA, to examine larval density, species composition, and parasitism of heliothines on this wild host plant. Insects were collected from the end of June through October. The largest densities (based on the number of caterpillars per sweep) of heliothines were over one larva per sweep. Overall, 49.5% of the collected caterpillars were determined to be tobacco budworms, while 50.5% were corn earworms. Parasitism rates ranged from approximately 1–30%, increasing throughout the season. In general, densities of heliothines encountered on A. ostryifolia were greater than densities reported for other wild host plants. Hophornbeam copperleaf is an important natural refuge for both heliothines from Bt toxins and synthetic insecticide applications.

Effect Infestation by Sesamia cretica L. Insect in some Characteristics of Growth for Varieties of Yellow Corn

This observe changed into carried out in the fields of Al-Hawija location of Kirkuk Governorate for the reason of reading the assessment of a few sorts of yellow corn for contamination through the corn stalk insect (Sesamia cretica L) and the impact of the insect infestation on a few traits and boom of yield of a few yellow corn cultivars. The maximum contamination fee of the ZOAN cultivar changed into 7.50% in comparison to the bottom contamination fee with inside the Samuray 34 cultivar of 0.50 % after a duration of 20 days of germination, however after forty days the contamination fee changed into maximum at the ZOAN cultivar 45% and for the nearby range 37.30% in comparison to the Samuray 34 cultivar 4% only, and after 60 days, the contamination fee changed into 25.75% for the ZOAN variety and for the nearby 19%, in comparison to 4.70% for the Samuray 34 variety. The number of caterpillars for each plant ranged between (0.30-2.70) for each plant for the studied cultivars. As for the average number of shoots for each plant, it ranged between (0.30-3) for each plant for the studied cultivars, as it was the lowest for the Samuray 34 cultivar and the highest for Sweetened (local) cultivar. Sweetened (local) cultivar, Wazawan, recorded the highest percentage of shoot lengths for each plant, as it was 9.30% and 7.50%, respectively, compared with the rest of the studied cultivars, as it was the lowest for the Samuray 34 cultivar, 1.33% of the plant, and for the Konstiz cultivar 3.60%, and for the Jameson cultivar 6%, while there were clear significant differences. In the percentage of shortening in the number of seeds and the values of loss in the weight of 100 grains, as well as the percentage of shortening in the crop, as the percentage of loss in the number of grains for the Samuray 34 variety was 12.33%, and the highest was for the Zawan variety by 18%, compared to the percentage of loss in Sweetened (local) variety amounted to 17.30%. The Samuray 34 cultivar recorded the lowest percentage of shortening in the weight of 100 grains, as it was 6% compared to the ZOAN cultivar, 8.60% compared to the rest of the studied cultivars, which was reflected in the percentage of loss in the total crop, as the percentages ranged between (19-24) %, as the Samuray 34 cultivar recorded the lowest percentage. It amounted to 19%, compared to 22.67% for the Zawan variety, and for Sweetened (local) 24%, compared to the rest of the maize varieties. The best cultivar was the Samuray 34 cultivar for use in breeding programs for corn stalk borer control.

Influence of Plant Resistance in Certain Genotypes of Green Gram on Insecticide Tolerance on Spotted Pod Borer, Maruca vitrata (Geyer)

Ten genotypes of green gram viz., WGG-42, LGG-407, PM-115, MGG-360, PM-110, LGG-410, PM-112, TM-962, LGG-450 and LGG-460 were screened for their susceptibility to Spotted pod borer, Maruca vitrata (Geyer) infestation at wetland farm, S.V.Agricultural College, Tirupati in a randomized block design (RBD) during the late Kharif season of 2014. Two crops were raised one at during last week of August-2014 and second was raised durin second week of September-2014. Readings on the number of Maruca webbings per plant, total number of caterpillars per plant and per cent infestation were taken at weekly intervals. Field screening experiments which were conducted on green gram genotypes against M. vitrata infestation revealed that WGG-42, TM-962 and MGG-360 were observed resistant, moderately resistant and susceptible reaction based on number of webbings per plant and number of caterpillars per plant. Further investigation on feeding preference of Maruca by free-choice and no-choice techniques on selected genotypes of green gram in the laboratory to confirm the resistance ranking observed in the field screening have yielded similar resistance reaction to Maruca infestation. Larvae of the first instar were allowed to feed on the susceptible and resistant genotypes of green gram upto third instar. At the third instar stage, they were allowed for topical bioassay application with Chlorpyriphos insecticide after taking the larval weights. The larvae which fed on the WGG-42 (resistant) gave LC50 (Lethal Concentration) and LD50 (Lethal Dose) values of 1.39 µL/ml and 36.98 µg/g and the larvae which fed on the MGG-360 (susceptible) gave LC50 and LD50 values of 1.63 µL/ml and 36.85 µg/g.

USE OF VAIEGO, SC IN CONTROL OF LEPIDOPTERA CABBAGE PESTS

Results of evaluation of biological efficiency of Vaiego insecticide, SC in control of lepidoptera cabbage pests are presented. A high, up to 100 % protective effect of the studied preparation against cabbage moth (Plutella xylostella L.) and cabbage scoop (Mamestra brassicae L.) was established in the consumption rates of 0,15 and 0,25 l/ha. The use of the insecticide Voliam Targo, SC (0,8 l/ha) made it possible to limit the number of caterpillars of cabbage moth by 96,9 %, cabbage scoop by 100 %. It was noted that the biological efficiency of Koragen, SC reached 100 % in relation to pests. A rather long-lasting effect was shown, for 14–28 days, on the populations of cabbage moth and cabbage scoop of all insecticides studied.

Efficacy of vegetable oil extracts for control of insect pests of tomato in Southern Benin

Pests are a menace to production of tomato (Lycopersicon esculentum Mill.) in sub-Sahara Africa. The objective of this study was to evaluate the efficacy of oil extracts of selected common plants for control of pests of tomato in Benin. The study was carried out on the Togba market garden sites in Benin. The botanical pesticides (Tephrosia purpurea, Ricinus communis, Thevetia neriifolia and Cashew Nut Shell Cold Liquid (CNSL cold) were compared with a biological insecticide (Topbio), a synthetic insecticide (Lambda cyhalothrin) and an untreated negative control. The fish model and the generalised linear mixed or fixed effects model were used to explain the number of caterpillars per plot as a function of the products tested during the different plant phases. Tephrosia purpurea oil, cold CNSL, Topbio and lambda cyhalothrin treatments significantly reduced H. armigera, S. littoralis and T. absoluta populations. The average yields of marketable tomato ranged from 7.20 ± 0.89 t ha-1 for the controls and 21.14 ± 3.56 and 20.46±1.98 t ha-1 for the plots treated with Tephrosia purpurea and CNSL cold on tomato, respectively. Plots treated with the synthetic insecticide lambda cyhalothrin gave the best yields (31.15±3.20 t ha-1). Of all the extracts tested, cold extracted CNSL and T. purpurea oil showed very high larvicidal activity at doses of 10%, compared to R. communis and T. neriifolia oil on the farm. The larvicidal activity of the extracts observed at low doses on H. armigera and S. littoralis larvae seems to offer an alternative advantage for the control of tomato pests.

Yellowstriped Oakworm (suggested common name), Peigler's oakworm, Anisota peigleri Riotte (Insecta: Lepidoptera: Saturniidae)

The yellowstriped oakworm, Anisota peigleri, is an occasional pest on oak trees in the southeastern United States. In Florida, outbreak populations defoliated laurel, water and Shumard oaks in Gainesville from 1996 until 2001. Even when defoliation is not severe, the falling frass (droppings) and large numbers of caterpillars are a major concern for many homeowners. Frass commonly stains driveways, walkways, pool decks and other outdoor structures.

PROPOZYCJA MONITORINGU GATUNKU NEPTIS RIVULARIS (SCOPOLI, 1763) W POLSCE

Hungarian Glider (Neptis rivularis), a species of butterfly of the family Nymphalidae, which in Poland is under partial species protection and is included in the Red list of threatened animals in Poland with the EN category. The occurrence and abundance of Neptis rivularis are strictly dependent on the presence of Spiraea salicifolia L., which is the host plant of the species. Limiting the range of the occurrence of the Neptis rivularis in Poland also results from the decline in the number of suitable habitats. This article presents a proposed methodology for monitoring based on the evaluation of indicators of population condition in the form of: number of adults, abundance index, number of caterpillars and population isolation, and indicators of habitat condition – presence of the Spiraea salicifolia and exposure to the sun of microhabitats. The concept of the population condition assessment methodology was based on non-invasive observation of adults and counting caterpillars. The concept of habitat condition assessment methodology is based on a strong relationship between the Neptis rivularis and the Spiraea salicifolia. It is proposed to annually monitor the Neptis rivularis population in at least a dozen research areas within the country. This proposed monitoring methodology requires pilot studies to be carried out within Neptis rivularis occurrence sites in order to assess the effectiveness of the presented assumptions of the monitoring methodology for this species.

Antixenosis in cotton genotypes (Gossypium hirsutum var. marie galante) to Spodoptera frugiperda (Lepidoptera: Noctuidae) mediated by trichome and gossypol densities

Cotton (Gossypium hirsutum L.) is one of the most important crops in Brazil and pest incidence limits its yields. The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), native to tropical and subtropical America, spread and rapidly became an invasive pest worldwide. It is a polyphagous pest that feeds on up to 353 plant species including cotton. The objective of this study was to evaluate the antixenosis to S. frugiperda in 27 cotton genotypes, comparing varieties with non- commercial genotypes. The attractiveness was estimated in no-choice and free-choice tests, offering leaf discs of the 27 cotton genotypes to S. frugiperda, and counting the number of caterpillars feeding at 3, 5, 10, 15, and 30 minutes and 1, 2, 6, 12, and 24 hours after their release. The numbers of trichomes and gossypol glands per cm2 were measured on abaxial and adaxial surface. The free-choice test was performed in a randomized block design with the 27 genotypes (treatments) and 20 arenas (replicates). The no-choice assay was conducted as a completely randomized design with 18 genotypes and 20 replicates. The non-commercial genotypes PI0440, CE0467, PI0416, BA0512 and MA0425 presented antixenosis against S. frugiperda. In the free-choice test the cultivar BRS Buriti and the genotype PI0429 were the most attractive to S. frugiperda, while in no-choice test, the genotype PI0429 was the most attractive. High trichome density and gossypol glands did not influence the attractiveness of S. frugiperda in cotton genotypes, while the absence of trichomes was repellent to the caterpillars. There is polymorphism among cotton genotypes to attractiveness to the pest, and the genotypes with antixenosis can be used in future study in plant breeding program as donor source of resistance to S. frugiperda

ОЦЕНКА СОРТОВ НА УСТОЙЧИВОСТЬ АГРОЦЕНОЗОВ СОИ К ХЛОПКОВОЙ СОВКЕ В УСЛОВИЯХ САМАРСКОЙ ОБЛАСТИ

Samer-2 is an undoubted leader in terms of attractiveness as a feed plant both in particular years and on average during the study years. A lower pest population, even in a year with a high number of pests, was shown by Cordoba variety. The rest of the studied varieties can be attributed to medium level of feed preference for cotton budworm. The observed pattern can presumably be explained by the difference in chemical composition of different varieties of soybean, which should be confirmed by further research, as well as by density of soybean plants. The best varieties in terms of protein content in our studies were Prudence, Alaska and Protina; the latter variety does not consistently accumulate this protein, which depends on weather conditions and other factors. The lowest grain moisture was shown by Alaska soybean variety, the agrocenosis of which had a low plant density. And conversely, the wettest grain had Samer-2 variety with a high number of plants per 1 m2. On average, over three years of observation, the best and consistently high yield was shown by Cordoba variety, due to, for one of the reasons, high resistance to damage by the cotton budworm. An opposite situation was observed for Protina and Samer-2 variants, a significant number of caterpillars of the studied phytophage led to a substantial yield decrease of these varieties, especially in the year favorable for development of this pest. Prudence and Alaska variants can be classified as medium-suppressed varieties with medium yields. To obtain a stable phytosanitary situation and obtain high-quality soybean crop, it is more expedient to cultivate Cordoba (high-yield) and Prudence (high-protein) varieties, with application of Biosleep BV, Zh insecticide (4 l / ha) for effective protection against cotton budworm.

Performance of phytosanitary products for control of soybean caterpillar.

The present work evaluated the efficiency of applied biological control and chemical control of Chrysodeixis includens, and the management of this looper caterpillar in the field soybean crop. The experimental design was a randomized complete block design, consisting of six treatments applied only once: two different doses of Bacillus thuringiensis (Bt), 0.2 and 0.35 L ha-1; Metarhizium rileyi strain UFMS 02 (Mr), 2.0 and 5.0 kg ha-1; insecticide Flubendiamide (Fd) 20 mL ha-1; and the control. The reduction of the pest and the percentage of efficiency of the products along the development of the soybean, besides some phytotechnical parameters, were evaluated thirteen days after the application. In general, there was a decrease in the number of caterpillars after thirteen days of spraying, with the Bt treatment being 350 mL ha-1, which provided the greatest reduction in the population (96.2%) when compared to the control (6.7 %). Regarding efficiency, treatments containing biological products Bt (two doses) and Mr 5.0 kg ha-1 provided the best results: 95.88, 84.69 and 92.35%, respectively. Among the phytotechnical parameters evaluated, the biological treatments were superior to the chemical treatments in relation to the productivity and the number of pods per plant, not differing statistically among them.

On the broadcast independence number of locally uniform 2-lobsters

Let~$G$ be a simple undirected graph. A broadcast on~$G$ is a function $f : V(G)\rightarrow\NNNNN$ such that $f(v)\le e_G(v)$ holds for every vertex~$v$ of~$G$, where $e_G(v)$ denotes the eccentricity of~$v$ in~$G$, that is, the maximum distance from~$v$ to any other vertex of~$G$. The cost of~$f$ is the value $\cost(f)=\sum_{v\in V(G)}f(v)$. A broadcast~$f$ on~$G$ is independent if for every two distinct vertices $u$ and~$v$ in~$G$, $d_G(u,v)>\max\{f(u),f(v)\}$, where $d_G(u,v)$ denotes the distance between $u$ and~$v$ in~$G$. The broadcast independence number of~$G$ is then defined as the maximum cost of an independent broadcast on~$G$. A caterpillar is a tree such that, after the removal of all leaf vertices, the remaining graph is a non-empty path. A lobster is a tree such that, after the removal of all leaf vertices, the remaining graph is a caterpillar. In [M. Ahmane, I. Bouchemakh and E. Sopena. On the Broadcast Independence Number of Caterpillars. Discrete Applied Mathematics, in press (2018)], we studied independent broadcasts of caterpillars. In this paper, carrying on with this line of research, we consider independent broadcasts of lobsters and give an explicit formula for the broadcast independence number of a family of lobsters called locally uniform $2$-lobsters.

Total difference chromatic numbers of graphs

Inspired by graceful labelings and total labelings of graphs, we introduce the idea of total difference labelings. A $k$-total labeling of a graph $G$ is an assignment of $k$ distinct labels to the edges and vertices of a graph so that adjacent vertices, incident edges, and an edge and its incident vertices receive different labels. A $k$-total difference labeling of a graph $G$ is a function $f$ from the set of edges and vertices of $G$ to the set $\{1,2,\ldots,k\}$, that is a $k$-total labeling of $G$ and for which $f(\{u,v\})=|f(u)-f(v)|$ for any two adjacent vertices $u$ and $v$ of $G$ with incident edge $\{u,v\}$. The least positive integer $k$ for which $G$ has a $k$-total difference labeling is its total difference chromatic number, $\chi_{td}(G)$. We determine the total difference chromatic number of paths, cycles, stars, wheels, gears and helms. We also provide bounds for total difference chromatic numbers of caterpillars, lobsters, and general trees.

ИЗУЧЕНИE ДЕЙСТВИЯ АНТИБИОТИКОВ НА ВОЗБУДИТЕЛЯ НОЗЕМАТОЗА ТУТОВОГО ШЕЛКОПРЯДА

Fighting against the nosematosis of the silkworm is very difficult due to the fact that it is inherited. The development of effective therapeutic and preventive measures is an important problem of sericulture. The following research is aimed at studying the effect of new-generation antibiotics on the causative agent of silkworm nosematosis in the case of early diagnosis, which leads to the suspension of the pathogen development in the host organism, preserving the maximum number of caterpillars and the optimal yield of cocoons on silkworm feeding. Modern antibiotic preparations of different concentrations were tested during the research. The studies were carried out at the caterpillar phase by feeding them mulberry leaves sprinkled with drugs and at the grain phase by treating the slightly infected grain in solutions. The intensity of infection with nosematosis in the experimental variants when compared with the control variant is 33.5%. After feeding the caterpillars for the first 5 days of the V-th age, leaves treated with antibiotics, a decrease in the infection intensity by 9.5-18.0 absolute percent is determined. The greatest decrease in the extent of infection is observed in the variants with the preparations Sinurol 1,2 million units, Sinurol 2,4 million units, Metronidazole (750 and 500 mg), Ciprofloxacin (250 mg), and it amounted to 14,0-18,0 abs.%. The results are consistent with published data indicating that antibiotics have an inhibitory effect against parasitic protozoa, which include the causative agent of silkworm nosematosis.

Burning number of caterpillars

Graph burning is a deterministic discrete time graph process that can be interpreted as a model for the spread of influence in social networks. The burning number b(G) of a graph G is the minimum number of steps in a graph burning process for G. Bonato et al. (2014) conjectured that b(G)≤⌈n⌉ for any connected graph G of order n. In this paper, we confirm this conjecture for caterpillars. We also determine the burning numbers of caterpillars with at most two stems and a subclass of the class of caterpillars all of whose spine vertices are stems.

The efficiency of control of the number of Helicoverpa armigera Hbn. in sunflower sowings

The insect Helicoverpa armigera Hbn. (Lepidoptera: Noctuidae) is a widespread species in the Palearctic. It is considered one of the main pests of many agricultural crops, annually causing more than $ 2 billion of losses to agriculture in the world. Therefore, insecticide treatment of sowings is crucial in pest control. The frequent application of pesticides increases resistance in insects, resulting in an increase in dosage and (or) in the usage of new highly toxic chemicals. Consequently, the search for reliable means of pest control remains a problem. In 2017-2019, we studied the efficiency of insecticides against H. armigera in sunflower sowings at V.S. Pustovoit All-Russian Research Institute of Oil Crops (Krasnodar). In 2017, the colonization of sunflower heads with H. armigera caterpillars was at the level of 3.2 specimen/plant, in 2018 – 4.5 specimen/plant, in 2019 it reached 6.0 specimen/plant. Bifetrin + Chlorpyrifos, EC (87 %) and Chlorantraniliprole, SC (91 %) showed the highest biological efficiency. Fitoverm-M, EC was the best organic insecticide – 56 %. The treatment of sunflower plants with Beta-cypermethrin + Dimethoate, EC (standard) and Chlorantraniliprole, SC in a production experiment contributed to a significant decrease in the number of caterpillars – 71.7 and 97.0 %, respectively. The yield reliably exceeded the control one, the kept yield was 0.23-0.39 t/ha.

Trichogramma pretiosum in field release and under different temperatures in laboratory

ABSTRACT This study aimed to evaluate a strain of Trichogramma pretiosum native to the central region of the state Rio Grande do Sul, Brazil, under different temperatures in laboratory and the parasitism of Helicoverpa zea after releases in corn field. Trichogramma pretiosum females were kept at 18, 25 and 30 °C and had their parasitism potential evaluated. Nine plots (400 m2) of maize were installed in randomized blocks under the treatments: 1) staggered release of parasitoids in three different occasions, at three-day intervals; 2) a single release of parasitoids; 3) no release of parasitoids. Ears were collected every four days and the number of caterpillars and eggs of H. zea in the maize silk and the number of damaged ears were estimated. Evaluation started after the tassels growth and ended with the drying of the styles-stigmas. To estimate the grain mass and the ear number and mass, two lines in each plot were delimited and reserved at the end of the cultivation cycle. In laboratory, the highest parasitism rate occurred at 25 °C (35.54%) and the lowest longevity at 30 °C (6.8 days). A total of 1,063 H. zea eggs were collected in the field, 69.52% were parasitized. The mean parasitism rate was higher in T1 (staggered release, 82.77%) than in control (51.87%), but there was no difference in grain yield. Based on the parasitism capacity of the studied strain, it can be potentially used in programs of biological control of H. zea in corn crops of Rio Grande do Sul.

Efficiency of the preparation based on Bacillus thuringiensis and nuclear polyhedrosis virus against diamond back moth (Plutella xylostella)

Studies have been conducted to assess the effectiveness of bioinsecticide preparation based on the sporocrystalline complex Bacillus thuringiensis and the nuclear polyedrosis virus. Before the preparation usage, a significant excess of the economic threshold of harmfulness for the investigated pest was noted on the experimental area of 1 ha. In the first survey of the site, Plutella xylostella caterpillar numbers on one plant varied within 5-6 caterpillars range when 62% of white cabbage plants were settled. After 3 treatments with an experimental preparation, the number of caterpillars decreased to 98 sp./100 plants and biological efficiency was 80.4%. Also, the effectiveness of the biopreparation in comparison with chemical insecticides was proved by single-factor dispersion analysis (Fobs.= 9.05; Fcrit.= 5.98).

Вплив зрошення на розвиток совки озимої в посівах пшениці озимої та кукурудзи

Relevance of research. Irrigation is a precondition for stable production of agricultural products, especially in regions with insufficient and unsustainable moisture. Studies have shown that the application of irrigation provides a change in the structure, chemical composition of the soil, as well as affect its aeration. The result of artificial irrigation is a change in the intensity of physiological processes in plants, their biomass, species composition of weeds in agrocenoses. These factors further significantly affect the species and quantitative composition of the entomofauna of agrocenoses, including winter wheat and maize. The purpose of the study was to determine the effect of drip irrigation and sprinkling on phenological and biological features of turnip moth development. Therefore, one of the main tasks of the research is to determine the dependence of fluctuations in the number of phytophagus on the type of irrigation. Results of the research. It has been established that drip irrigation and sprinkling are effective measures of crops’ protection against damage and invasion caused by turnip moth. The most dangerous for maize plants is the turnip moth in the “caterpillar” stage of the I-II age of spring generation. Sprinkling irrigation during the period of mass egg’s deposition and the revival of caterpillars of turning moth contributes to a significant decrease (by 6,8-67,7%) in the share of this type of pest, compared to conditions without an irrigation. Corresponding results were also obtained from a study of the effect of the different irrigation types on oulema in winter wheat crops. That is, the amount of the indicated phytophage under irrigation conditions was less than 3–6 times compared with the control (without irrigation). It was proved that in the case of sprinkling, compared with the control (without irrigation), the number of caterpillars of younger ages L1-L2 over the years ranged from 0,2 to 6,2 sp./m 2 , while in the control the density was 3,3 – 14,5 sp./m 2 . It has been established that the caterpillars of turnip moth in conditions of high soil moisture are more susceptible to entomopathogenic species of entomophoric fungi Beauveria bassiana (Bals.) Vuill. and B. tenella (Delacr.). Minimal damage to the pest by the indicated pathogens was noted on the caterpillars of older ages L3-L4. Without an irrigation, the proportion of infected caterpillars was 2,2 – 0,5%, which is 1,6 – 2,4 times less than sprinkling, and 1,1 – 4,8 times drip irrigation. Crop irrigation also affects the distribution of the pests over the soil layers. In dry and loose soil in rainfed areas, larvae and pupae of turnip moth occur at a depth of 10-20 cm, while in moist, compacted soil of irrigated fields up to 5 cm. This makes them more accessible for destruction during cultivation and other surface treatments. Conclusions. In the conditions of the Dry Steppe of Ukraine the terms of the turnip moth occurrence varies by years, depending on the weather factors. On average, during the years of research, the occurrence of a dangerous stage of turnip moth’ development (caterpillars) was observed in the third decade of May - the second decade of June. Irrigation and drip irrigation are effective enough to reduce the density of the phytophage population. During the observation period, it is noted that irrigation of crops by the method of sprinkling is a significant factor in limiting the number of caterpillars of turnip moth. The reduction in the proportion of the pest relative to the conditions without irrigation was 6.8-67.7%. The caterpillars of the L1-L2 younger generations are more vulnerable to the effects of irrigation in maize crops. It is noted that irrigation maximally reduces the number of eggs of turnip moth and pests in the early stages of development. That is, clarification of the effects of irrigation on the development of biting scoops in maize agrobiocenoses in the Steppe Dry region allows to determine the degree of threat to crops, reduce the density of the phytophage population, as well as to plan and adjust the main measures of crop protection against these damage.

Silicon fertilization as a tool to control diamondback moth in cabbage plants

Integrated pest management strategies are among the factors promoting plant resistance to pests, and mineral fertilization with silicon may increase this resistance. Thus, the objective of this research was to evaluate the control of diamondback moth (DBM), Plutella xylostella (Linnaeus, 1758) (Lepidoptera, Plutellidae) through foliar fertilization with silicon in cabbage crops. The experiment was conducted in the vegetable producing area of the Agua Limpa Farm of the University of Brasilia, Distrito Federal, Brazil. The experimental design was a randomized block with nine treatments and four replicates, totaling 36 plots. The treatments applied consisted of Agrosilicon® (10.5% Si) (T1), Sifol® (12% Si) (T2), Decis® 25 EC (Deltamethrin 25 g L -1 ) (T3), Dipel® SC ( Bacillus thuringiensis , 33.60 g L -1 ) (T4), Agrosilicon® + Decis® (T5), Agrosilicon® + Dipel® (T6), Sifol® + Decis® (T7), Sifol® + Dipel® (T8) and a Control (T9). Foliar fertilization with Agrosilicon® and Sifol ® were performed weekly and the insecticides Decis® and Dipel® were applied according to the damage level established for DBM in cabbage crops. Foliar fertilizations with silicon, singly or in combination with chemical and biological insecticides - T2, T7 and T8, were the best strategy to control DBM, resulting in the lowest number of caterpillars per plant, lowest leaf damages and best aesthetic value of plants. Foliar fertilization with silicon has significant potential to control diamondback moth in cabbage crops.