2026-BKUBTS SINAV ÖNCESİ HIZLANDIRILMIŞ EĞİTİM - BAYKÜ

Purpose and Exam Focus

Mehmet Koç presents a fast-paced review for the 2026 Plant Protection Products Dealer and Wholesaler Exam. The session concentrates on:

• Typical symptoms used to identify important plant diseases and pests.
• Key disease and pest-control methods.
• Insect anatomy and characteristic damage.
• Modes of action of selected insecticides and fungicides.

The presenter says the material is intended as a high-yield review rather than a complete survey. He advises candidates to take notes, memorize the regulatory and numerical sections separately, and give particular attention to characteristic symptoms, common disease names, and control methods. He also warns that some scientific names in the auto-generated subtitles appear corrupted and should be checked against reliable study materials.

Plant Disease Fundamentals

The Disease Triangle

Disease develops when three conditions occur together:

1. A pathogen capable of causing disease is present.
2. A susceptible host plant is available.
3. Environmental conditions are favorable.

Relevant environmental factors include temperature, humidity, rainfall, light, wind, and human activity. A pathogen’s virulence, spore production, spread, and inoculum level also affect disease risk. Host susceptibility can depend on the plant’s genetics, physiology, and developmental stage.

Resistance, Susceptibility, and Disease Agents

• Resistance is the plant’s ability to prevent or limit infection through its genetic traits and defense mechanisms.
• Susceptibility is a lack of effective resistance, making infection and disease more likely.
• Abiotic (non-living) causes can produce symptoms that resemble disease, such as nutrient deficiencies or frost injury. The presenter calls these disease-causing non-living factors physiogens.
• Biotic (living) disease agents—including fungi, fungus-like organisms, bacteria, viruses, viroids, and phytoplasmas—are described as pathogens and generally act parasitically.

Nutritional Relationships

• Saprophytes feed on dead or decaying material.
• Mutualism benefits both partners. Examples include Rhizobium bacteria fixing nitrogen for plants and mycorrhizal fungi helping plants access nutrients.
• Commensalism benefits one partner without materially affecting the other.
• Parasitism benefits the pathogen while harming the plant.
• Facultative saprophytes normally cause disease on living tissue but can survive on dead tissue.
• Facultative parasites normally live on dead material but can infect living tissue.
• Obligate parasites (biotrophs) require living tissue to feed and reproduce.

Stages of Disease Development

The presenter outlines the disease process as follows:

1. Inoculation: The pathogen first contacts the host.
2. Penetration: The pathogen enters through openings or wounds, or by penetrating plant tissue.
3. Infection: It feeds, grows, and multiplies in the host.
4. Incubation: The interval between initial infection and the first visible symptoms.
5. Development and spread: The pathogen continues to multiply and colonize while conditions remain suitable.

Monocyclic and Polycyclic Diseases

• Monocyclic diseases produce one main infection cycle in a season, generally involving primary inoculum but no repeated secondary cycles.
• Polycyclic diseases produce repeated secondary inoculum and infections during a season, so they can spread rapidly and present greater epidemic risk.

The presenter gives Fusarium wilts, smuts, and potato ring rot as examples of monocyclic diseases, and rusts, powdery mildews, apple and pear scab, and several leaf-spot diseases as polycyclic examples. The exact examples and scientific names should be verified because some are unclear in the subtitles.

Major Pathogen Groups and Crop Examples

Important Structural Clues

• Downy mildew agents are described as fungus-like rather than true fungi. The presenter emphasizes sexual oospores and motile, water-moving asexual zoospores.
• Powdery mildew agents are obligate parasites. The presenter identifies the winter-survival structure as a cleistothecium or cleistothecium-like structure and notes that these diseases generally affect above-ground green tissues.
• Rust diseases generally form spore-bearing pustules on above-ground plant parts. They are obligate parasites; the presenter emphasizes resistant varieties as an important control measure.
• Smut and bunt diseases commonly survive unfavorable periods as dark, powdery teliospores and are often managed with seed treatment.
• Root and collar rots, fruit rots, leaf spots, and cankers can have multiple possible causes, including fungi, fungus-like organisms, and bacteria. The presenter cautions against assuming that a symptom has only one possible cause.

Cereals

• Barley leaf blight and barley streak leaf spot are distinguished by their symptoms and control recommendations. The talk describes seed and foliar treatment for the former, and seed treatment for the latter.
• Smut and bunt diseases of wheat and barley are associated with dark teliospores; seed treatment is emphasized. The presenter also mentions cultural timing measures for wheat smut.

• Wheat rusts:

  • Yellow or stripe rust is associated with Puccinia striiformis and can form line-like, “machine-stitch” pustules.
  • Brown rust is described as primarily a leaf rust.
  • Black or stem rust is associated with pale, torn-looking areas around ruptured tissue. Resistant varieties are highlighted as a key control method.

• Septoria leaf spot of wheat is associated with small black pycnidia in necrotic leaf areas; the presenter calls attention to seed treatment as well as foliar treatment.

• Fusarium head blight can cause ears to turn white.
• Cereal powdery mildew is an obligate parasite. The presenter discusses foliar treatment and, as an exception, seed treatment in cereals.
• Corn smut forms swollen, gall-like structures. The talk distinguishes localized common smut from a more systemic head-smut form and says that the two differ in their control options.
• Rice blast is identified by name, with seed treatment and a pesticide combination authorized for drone application mentioned in the presentation.
• Rice root and collar rot is associated with Bakanae syndrome.
• Rye ergot infects around flowering and forms hard, elongated sclerotia in place of grains. The presenter warns that contaminated grain can cause serious poisoning in people and animals.

Other Crops and Fruit Trees

The presenter gives a series of symptom-to-disease associations, including:

• Sunflower charcoal rot: Dry, dying plant tissue; favored by hot, dry conditions.
• Sunflower downy mildew: Described as systemic, with seed treatment mentioned as a control measure.
• Tobacco powdery mildew versus tobacco blue mold: These should not be confused. The talk distinguishes the white, powdery appearance from bluish growth beneath yellowish leaf spots.
• Soybean Cercospora diseases: One is linked to frog-eye leaf spots and another to purple seed stain.
• Spinach leaf spot and some other crop diseases are associated with bird’s-eye-like markings.
• Chickpea anthracnose is linked to a colloquial “cloud” disease name; the talk mentions both seed and foliar treatment.
• Potato wart disease can persist in soil for many years and is treated as a quarantine concern.
• Gray mold is said to survive unfavorable conditions in a durable structure and can begin with ghost-like spots.
• Pear and apple rusts are associated with distinctive spore structures beneath leaves.
• Apple and pear scab produce scab-like lesions. Apple powdery mildew is presented as an exception that can survive as mycelium rather than the usual winter structure.
• Grape powdery mildew can crack berries; the presenter says unnecessary spraying after fruit drop is not advised.
• Grape anthracnose, strawberry leaf spot, and some other diseases are associated with bird’s-eye-shaped marks.
• Plum pocket disease produces enlarged or distorted fruit that lacks a normal stone.

Bacteria, Phytoplasmas, Viruses, and Viroids

• The presenter reviews Gram-positive and Gram-negative bacteria, contrasting cell-wall features and staining colors.
• Cotton angular leaf spot is associated with black-arm symptoms and seed transmission.
• Bacterial wilt and ring-rot agents in potatoes are distinguished partly by whether bacterial ooze appears spontaneously or after pressure is applied.
• Potato common scab causes scab-like tuber lesions. The presenter recommends keeping soil pH below 5.5 and mentions sulfur, while noting limitations in available seed treatments.
• Bacterial fruit spot of watermelon can cause fruit cracking and bacterial ooze.
• In tomatoes, bacterial spot is distinguished from bacterial canker and wilt. The latter is associated with vascular blockage and canker-like lesions; bird’s-eye markings on fruit are also mentioned.
• Agrobacterium crown/root gall is linked to T-plasmids and transfer of T-DNA into plant cells.
• Fire blight is associated with a shepherd’s-crook bend in shoots and can spread through flowers.
• Several phytoplasmas are linked to distinctive symptoms, including acorn-shaped citrus fruit, witches’-broom-like shoots, and blackened grapevine tissue.
• Examples of viral disease symptoms include fern-like tomato leaves, thread-like leaves, ring spots, spoon-shaped leaf curling, and stunting.
• The talk identifies particular vectors for several viruses, including thrips, whiteflies, aphids, and dagger nematodes.
• Sharka virus is associated with stone fruits and ring symptoms; eradication of diseased trees is described as the main control approach.
• The presenter says that most plant viruses discussed contain RNA, while naming three exceptions said to contain DNA. Because the subtitles are unclear in places, these details should be checked in a reliable reference.
• Viroids are illustrated with potato spindle-tuber and citrus viroid diseases, with symptoms such as shortened internodes, distorted tubers, graft incompatibility, and internal bark markings.

Insect Anatomy and Pest Identification

Insect Structures

• An insect antenna has three main sections: scape (attached to the head), pedicel, and flagellum.
• The thorax has three segments: prothorax, mesothorax, and metathorax.
• Legs arise from all three thoracic segments; wings arise from the mesothorax and metathorax.
• Leg segments, in order, are coxa, trochanter, femur, tibia, and tarsus.
• The talk distinguishes biting-chewing, piercing-sucking, rasping-sucking, lapping, and siphoning mouthparts, and notes that mouthparts can change between larval and adult stages.

Characteristic Pest Damage and Control Points

The presenter uses visible symptoms to help identify important pests. Examples include:

• Cereal flies whose larvae damage stems and cause a “dried umbilical cord” appearance.
• Corn borers whose feeding can make plants look wind-damaged.
• Hessian fly and sunn pest damage to cereals, including weakened stems and white ears; the talk distinguishes the stage targeted for control.
• Cereal leaf beetles, whose feeding produces pale streaks on leaves.
• Western corn rootworm larvae, which can cause corn to bend into a gooseneck shape.
• Cotton pink bollworm, associated with rosette flowers and blind bolls; early emergence before suitable reproductive structures are present is described as “suicidal emergence.”
• Tobacco thrips, associated with whitening of leaf veins; the potato/tobacco moth is linked to swelling in tobacco stems.
• Carrot fly larvae, which cause rusty-looking root damage; cabbage gall pests cause swellings around the root and collar.
• Potato beetle adults, called “pajama bugs” because of their striped appearance.
• Cutworms, whose larvae curl into a C shape when disturbed.
• Legume flower beetles: Adults damage flowers and buds; the presenter mentions blue traps.
• Apple woolly aphid, associated with galls or swellings on shoots and trunks.
• Grape pests that damage buds can produce frost-like symptoms; the presenter differentiates a bud-feeding moth from weevils.
• Grape phylloxera has root-feeding and leaf-feeding forms; resistant American rootstocks are mentioned as a cultural control.
• Mediterranean fruit fly larvae feed inside fruit; the presenter notes that egg-laying is not expected below a stated temperature threshold.
• Carob moth larvae can move from feeding on mealybug secretions to entering pomegranates and damaging seeds.
• The “bloody scale” insect is identified by red fluid released when crushed.
• Spotted-wing drosophila is distinguished from fruit flies that mainly infest already-rotten fruit.
• Natural enemies of citrus mealybugs are mentioned as biological-control agents.
• Pistachio wood-boring pests can be trapped in bundles of dried prunings and destroyed during winter.
• Hazelnut weevil larvae feed inside nuts; stink bugs cause yellowing, blackening, or stained kernels.
• Tomato rust mite causes bronzing, hardening, and cracking; broad mite damage can resemble herbicide injury.
• Wheat gall nematode produces galls and can persist for many years; rice white-tip nematode causes white leaf tips; potato rot nematode causes tuber decay and a honeycomb-like appearance.

Pesticide Modes of Action

The final section reviews selected mechanisms. These are presented as exam-study concepts, not as a complete pesticide-use guide.

Insecticides

• Acetylcholinesterase inhibitors: Carbamates and organophosphates. The presenter says these disrupt nerve signaling and can cause over-stimulation, convulsions, and death.
• Sodium-channel modulators: Pyrethroids, including compounds with names often ending in “-thrin”; they disrupt nerve transmission.
• Nicotinic acetylcholine receptor agents: Discussed as affecting nerve signaling.
• Juvenile-hormone receptor modulators: Pyriproxyfen is highlighted as a growth regulator that disrupts normal development.
• Electron-transport inhibitors/fumigants: Phosphine-producing compounds are described as interfering with energy production and ATP synthesis. The presenter distinguishes direct fumigant action from zinc phosphide, which releases phosphine after ingestion by rodents.

Fungicides

• Phenylamides: Described as stopping RNA synthesis by affecting RNA polymerase.
• Heteroaromatic fungicides: Described as interfering with DNA processes.
• Benzimidazoles: Disrupt microtubule formation and cell division.
• Strobilurins: Inhibit mitochondrial respiration and ATP production.
• Aromatic hydrocarbons and fungicidal carbamates: Discussed as interfering with lipid synthesis and membrane function. The presenter stresses that fungicide carbamates should not be confused with insecticide carbamates.
• Triazoles and imidazoles: Inhibit sterol/ergosterol biosynthesis and thereby disrupt fungal membrane integrity.
• Carboxylic-acid fungicides: Inhibit cell-wall biosynthesis.
• Defense-inducing products: Act indirectly by stimulating plant defenses rather than directly attacking the fungus. Fosetyl-aluminum and phosphorous acid are given as examples.

Speakers and Sources Featured

• Mehmet Koç is the sole presenter, identified in the subtitles as an agricultural engineer associated with the Baykü/BKÜ exam-preparation materials.
• The presenter refers to past questions from 2020, 2024, and 2025 and to ÖSYM exam content. These are references made by the presenter, not separate speakers.
• No guest speakers or interviewees appear in the subtitles.