1. Introduction

Fruit growing in the world is one of the most important sources of valuable nutritional and healing properties, which are of great importance for ensuring healthy and balanced nutrition of people. It is known that many fruit plants have not only high taste, but also decorative qualities.

In the modern world there are about 50 botanical families, uniting more than 300 genera and more than 1500 species of fruit plants. In practical fruit growing, about 200 fruit berry and nut crops are used, of which about 100 are used as industrial ones.

For Uzbekistan, the topic of fruit growing development has recently become particularly relevant due to the growing demand for these products and the availability of great opportunities for their cultivation. Uzbekistan grows 240 varieties of apples, 300 varieties of peaches, 140 varieties of cherries, 50 varieties of cherries, a large number of varieties of pears and quince [3].

In Uzbekistan, fruit trees are also affected by various pests, including parasitic nematodes, and in subsequent years these pests slow down the growth and development of fruit trees and seriously damage their productivity.

In foreign countries, research on the fauna, taxonomy, ecology of nematodes of fruit trees, as well as on the development of measures to combat parasitic species was carried out by A. Bello, E. Laborda [8], K.V. Akopyan, R.S. Mkrtchyan, S.X. Talstyan, A.P. Khurshudyan [2], M. Di Vito, A.M. Simeone and F. Catalano [13], Faisal Hussain, Saadullah Khan Laghari, Diam Ali Darban, Farzana, and Muhammad Akbar [14], N. Chihani-Hammas, L. Hajji-Hedfi, Y. Qing, A. Badiss, H. Regaieg, N. Horrigue-Raouani [10], Nayba, N. Javed, S.A. Khan, Z. Ullah and H.U. Khan [20], A. Bivol, I. Toderaș, E. Iurcu-Străistaru, Ș. Rusu, E. Bivol [9], I.P. Kazachenko, T.I. Mukhina [16], J.A. Karapetyan [17], R.A. Tiev, T.S. Skarbilovich [25], A.A. Razzhivin [9] and other scientists.

In Uzbekistan, nematodes of fruit trees and the damage caused by parasitic species of these plants have not been sufficiently studied. Phytohelminthological studies on the fauna and ecology of nematodes of fruit trees were carried out in Uzbekistan by E.T.Turaev, Sh.Kh. Khurramov [26], K.S. Ibragimov [15], A.S. Bekmurodov, G.B. Aramova [4], A.S. Bekmurodov, E.A. Saidova, Sh.A. Bobokeldiyeva, S.H. Jurayeva [5], A.S. Bekmurodov, M. Yakhshiboeva, S. Topilova, D. Normatova [6], A.S. Bekmurodov, M. Raxmatova, N. Iskandarova, G. Aramova [7], E.A. Saidova [25] and other researchers.

2. Materials and Methods

Our research was carried out in 2021–2025 in the problem laboratory “Helminthology” at the Department of Zoology of Termez State University (laboratory research) and orchards (field research) in the territory of Uzbekistan.

To identify the fauna of parasitic nematodes of fruit trees in Uzbekistan, samples of plants and root soil of apple (Malus domestica L.), common apricot (Prunus armeniaca L.), common peach (Persica vulgaris Mill.), pear (Pyrus communis), cherry (Cerasus avium L.), plum (Prunus domestica), walnut (Juglans regia) and pecan (Carya illinoinensis) were collected and analyzed.

To study the nematode fauna of fruit crops in Uzbekistan, 1,400 plant and 1,400 soil samples were collected and analyzed.

To identify the species composition of nematodes and the patterns of their distribution in the root system and root soil of fruit trees, we used the route method, widely used by phytohelminthologists in the CIS countries [18,21,22].

The collected samples were analyzed in the phytohelminthological laboratory at Termez State University. The modified Berman funnel method was mainly used to extract nematodes from soil and plant samples. The nematodes were cleared in a mixture of glycerin and alcohol (1:3) and for office processing of the material, permanent preparations were prepared on glycerin using the Seinhorst method [27]. Soil samples were analyzed for the presence of cyst-forming nematodes using the Dekker method [12].

The species composition of nematodes was studied under an MBR-3 microscope with a light filter. To determine the nematode species, morphometric indices obtained using the generally accepted De Man formula [11] in its modification according to Micoletzky [19] were used.

The degree of dominance of nematodes in plant and soil samples was determined from the percentage of individuals of individual species to the total number of those detected by Witkowsky [28]. In this case, dominant and/or eudominant species are those that make up more than 10% of all those detected, dominants 5.1-10%, subdominants 2.1-5%, recedents 1.1-2%, subrecedents or rare species less than 1% of individuals.

3. Results and Discussion

Data on the fauna of parasitic nematodes of fruit trees in Uzbekistan. As a result of phytohelminthological studies conducted on fruit crops (apple trees, common apricot, common peach, cherry, plum, pear, walnut and pecan) in the territory of Uzbekistan, we identified 33 species of nematodes. The identified species belong to 2 orders (Dorylaimida, Tylenchida), 4 suborders (Dorylaimina, Tylenchina, Criconematina, Hexatylina), 5 superfamilies (Dorylaimoidea, Dolichodoroidea, Hoplolaimoidea, Criconematoidea, Anguinoidea), 8 families (Longidoridae, Xiphinematidae, Tуlenchorhynchidae, Hoplolaimidae, Pratylenchidae, Meloidogynidae, Paratylenchidae, Anguinidae), 10 subfamilies (Longidorinae, Xiphinematinae, Tуlenchorhynchinae, Merlininae, Rotylenchinae, Rotylenchoidinae, Pratylenchinae, Meloidogyninae, Paratylenchinae, Anguininae) and 13 genera (Longidorus, Xiphinema, Tylenchorhynchus, Bitylenchus, Quinisulcius, Merlnius, Scutylenchus, Rotylenchus, Helicotylenchus, Pratylenchus, Meloidogyne, Paratylenchus and Ditylenchus).

In the taxonomic composition of the nematode fauna of fruit trees in Uzbekistan, nematode species of the family Tуlenchorhynchidae (10 species) dominated, making up 30.3% of all species found (Table 1).

Table 1. Taxonomic composition of nematodes of fruit trees of Uzbekistan (by families)

The research results show that the species Longidorus elongatus, Xiphinema elongatum, Tylenchorhynchus brassicae, T. claytoni, Bitylenchus dubius, Merlinius brevidens, Rotylenchus robustus, Helicotylenchus dihystera, H. erythrinae, Pratylenchus pratensis, Mеloidogyne incognita and Ditylenchus dipsaci are found in large quantities in fruit orchards in Uzbekistan, causing serious damage to the growth, development and productivity of fruit trees.

Efficiency of using plant extracts against parasitic nematodes. Currently, the use of plant extracts against phytoparasitic nematodes is one of the environmentally friendly, economical and effective methods of pest control. This method is preferred because it provides the opportunity to control parasitic nematodes using harmless natural substances instead of harmful chemicals that are dangerous to organisms common in various habitats. Currently, plant extracts are used to control the population of parasitic nematodes, limit their growth, reproduction and activity, or completely eliminate these pests.

The mechanism of action of plant extracts on parasitic nematodes is as follows:

Nematode poisoning: Alkaloids, flavonoids and essential oils of some plants are toxic to nematodes.

Nematode Removal: The smell and secretions of some plants repel nematodes from the soil.

Limiting the reproduction of nematodes: extracts slow down the growth and egg-laying of parasitic nematodes.

In our study, we used plant extracts against parasitic nematodes on fruit trees.

Experiment 1. Field studies were conducted in the farm "Bodomzor Angor" of the Angor district of the Surkhandarya region. This territory was determined to be moderately infested with parasitic nematodes.

In this experiment we used hot pepper extract (Capsicum annuum L.) against parasitic nematodes of walnut seedlings (3-4 years old).

In our studies, the biological effectiveness of plant extracts against parasitic nematodes was determined using the Abbott formula [1]: Bs = (Ab - Ba) / Ab) x 100%. Here: Bs - is the biological efficiency; A - is the number of pests (nematodes) before treatment in the experimental variant; a - is the number of pests (nematodes) noted in the following days after treatment; B - is the number (density) of pests (nematodes) before treatment in the control (untreated) variant; b - is the number of pests (nematodes) noted in the following days in the control variant.

In our study, two plots of 100 m² were selected where the extract obtained from hot pepper plant was tested against phytoparasitic nematodes found in walnut orchards at three different application rates (by applying 500; 700; 1000 ml of working solution to each seedling). The extract was applied to the roots of the plants every 12 days. The application of the extracts was repeated 4 times. According to the results of the study, in the area treated at a dose of 1000 ml of extract/seedlings, the number of parasitic nematodes, which seriously damage the walnut plant and significantly harm its growth, development and yield, decreased by 94.2% (Table 2).

The experiments were carried out in the following order and doses and the corresponding results were obtained: (Table 2.)

Table 2. Efficiency of hot pepper extract against parasitic nematodes of walnut plants (Field experiment. 2024, Angor district, Bodomzor Angor farm)

Experiment 2. Field research was conducted in the orchards of the Surkhandarya Research Station of the Research Institute of Horticulture, Viticulture and Winemaking named after M. Mirzaev.

In this experiment we used hot pepper extract (Capsicum annuum L.) against parasitic nematodes of apple seedlings (3-4 years old). In these experiments the type of extract, dose, method and time of application were the same as when applied to walnut seedlings (Table 3.).

Table 3. Efficiency of using hot pepper extract against parasitic nematodes of apple trees (Field experiment. 2025, Surkhandarya Research Station of the Research Institute of Horticulture, Viticulture and Winemaking named after M. Mirzaev)

From Table 3 it is evident that in the area treated with a dose of 1000 ml of extract/seedlings, the number of parasitic nematodes of apple trees decreased by 94.2%.

4. Conclusions

Thus, as a result of phytohelminthological studies conducted on fruit trees in the territory of Uzbekistan, 33 species of nematodes were identified, belonging to 2 orders, 4 suborders, 5 superfamilies, 8 families, 10 subfamilies and 13 genera.

In production conditions, a plant extract obtained from hot pepper (Capsicum annuum L.) was tested in a dose of 500; 700; 1000 ml/seedlings to combat parasitic nematodes of fruit trees (especially 3-4 year-old walnut and apple seedlings). High efficiency was recorded in a dose of 1000 ml/seedlings (93.4-94.2%).

As a result of the study, it can be concluded that the use of plant extracts, in particular hot pepper extract, in the fight against parasitic nematodes of fruit trees is one of the environmentally friendly and effective methods that allows you to fight nematodes with natural substances instead of harmful chemicals. Such extracts are used to limit the growth, reproduction and activity of nematodes or to completely destroy them. The extract limits the reproduction of parasitic nematodes, slows down their egg laying and growth.