UPHESC Assistant Professor Entomology PYQs

Concept: High-volume (hydraulic power) sprayers pump large volumes of dilute spray at high pressure, roughly 20–55 kg/cm².

1. Converting: 1 kg/cm² ≈ 14.2 psi, so 20–55 kg/cm² ≈ 300–800 psi.
2. Such pressure forces liquid through the nozzle to break it into droplets and to reach tall trees (orchard sprayers).
3. Manual pumps (rocker, foot) develop only about 7–17 kg/cm² (100–250 psi).

Short trick: High-volume power sprayer: 300–800 psi.

Concept: A hollow-cone/cone nozzle consists of a nozzle body, swirl plate (core), washer, disc with orifice and cap.

1. The swirl plate has slanted grooves that impart a rotational (swirling) motion to the liquid, which then breaks into a cone of droplets on leaving the orifice.

Short trick: Swirl = spin → cone nozzle.

Concept: Tomato spotted wilt virus (Tospovirus/Orthotospovirus) is transmitted only by thrips, notably Thrips tabaci and Frankliniella occidentalis.

1. Thrips acquire the virus as larvae and transmit as adults in a persistent-propagative manner.
2. WSMV is transmitted by the eriophyid mite Aceria tosichella; PSTVd spreads mechanically/through seed tubers (aphids only with PLRV).

Short trick: Tospo → Thrips (T–T).

Concept: Whiteflies (e.g. Bemisia tabaci) belong to Aleyrodidae (Hemiptera: Sternorrhyncha).

1. Pseudococcidae = mealybugs; Cicadellidae = leafhoppers; Eriophyidae = gall/rust mites (Acari, not insects).

Short trick: Aleyrodes (Greek 'flour-like') → white mealy wings → Aleyrodidae.

Concept: Bhindi (okra) yellow vein mosaic virus is a begomovirus (Geminiviridae).

1. Begomoviruses are transmitted by the whitefly Bemisia tabaci in a persistent, circulative manner.
2. Aphids transmit potyviruses/cucumoviruses; thrips transmit tospoviruses.

Short trick: Yellow vein / leaf curl (gemini) → whitefly.

Concept: Sugarcane mosaic virus (Potyvirus) is transmitted non-persistently by aphids, chiefly the corn leaf aphid Rhopalosiphum maidis (also Melanaphis sacchari).

1. It also spreads through infected setts.
2. Nephotettix transmits rice tungro; Thrips tabaci transmits TSWV.

Short trick: Sugarcane mosaic → maize aphid (R. maidis).

Concept: Citrus tristeza virus (Closterovirus) is transmitted semi-persistently by aphids; the brown citrus aphid Toxoptera citricida is the most efficient vector.

1. Diaphorina citri (Asian citrus psyllid) and Trioza erytreae (African psyllid) transmit citrus greening (huanglongbing) bacterium.

Short trick: Tristeza → Toxoptera (T–T); greening → psyllid.

Concept: Whitefly-borne begomoviruses (leaf curl, yellow vein mosaic) are transmitted in a persistent, circulative manner.

1. The virus is ingested, passes through the gut into the haemolymph, reaches the salivary glands and is injected with saliva.
2. Hence there is a latent period and the whitefly stays viruliferous for long (often for life).
3. Non-persistent (stylet-borne) transmission is typical of aphids and potyviruses.

Short trick: Whitefly + gemini virus = persistent circulative.

Concept: Onion thrips Thrips tabaci (Thripidae): egg → 2 larval instars → prepupa → pupa → adult.

1. The mature second-instar larva drops to the ground and the prepupal and pupal stages are passed in the soil (a few cm deep).
2. So soil application/irrigation and ploughing help reduce the population.

Short trick: Thrips: feed on plant, pupate in soil.

Concept: Sweet potato weevil, Cylas formicarius (Brentidae/Curculionidae), is the key pest of sweet potato (printed as 'termicarius').

1. Grubs tunnel in vines and tubers; infested tubers turn bitter and unfit for eating.
2. Amrasca biguttula biguttula = cotton/okra leafhopper; Agrotis ipsilon = cutworm; Phthorimaea operculella = potato tuber moth.

Short trick: Cylas – ant-like ('formica') weevil – sweet potato.

Concept: Ber fruit fly, Carpomyia vesuviana (Tephritidae), is the most destructive pest of ber (Ziziphus mauritiana).

1. Maggots feed inside the pulp, making fruits rot and drop; losses may reach 80–100%.
2. Virachola isocrates = anar (pomegranate) butterfly; Bactrocera spp. attack mango, guava, cucurbits.

Short trick: Ber → Carpomyia vesuviana.

Concept: Indian mustard is grown as a trap crop in cabbage/cauliflower against diamondback moth Plutella xylostella.

1. Recommended pattern: 2 rows of mustard after every 25 rows of cabbage (one row sown 15 days before and one 25 days after planting).
2. DBM prefers mustard for egg laying; the trap rows are sprayed or destroyed.

Short trick: Cabbage DBM → mustard trap (25:2).

Concept: Oriental fruit fly Bactrocera dorsalis (Hendel) is multivoltine.

1. Its life cycle takes only 3–5 weeks in warm weather, so it passes through many overlapping generations in a year (often 8–10 in the tropics).
2. Generation number varies with temperature and host availability, so no fixed small number fits.

Short trick: Fast life cycle + warm climate → many overlapping generations.

Concept: Lemon (citrus) butterfly, Papilio demoleus, belongs to Papilionidae (swallowtails).

1. Noctuidae = owlet moths; Jassidae (Cicadellidae) = leafhoppers; Coccidae = soft scales.

Short trick: Papilio → Papilionidae.

Concept: Early-instar caterpillars of the citrus (lemon) butterfly Papilio demoleus are dark brown with white patches – they resemble bird droppings (protective mimicry).

1. Later instars become green with an osmeterium (forked scent gland).
2. Leaf miner larvae live inside leaves; fruit-sucking moth larvae feed on weeds; borers live inside stems.

Short trick: Bird-dropping caterpillar on citrus → lemon butterfly.

Concept: In RBD the field is divided into homogeneous blocks; every block contains all treatments once.

1. Within each block the treatments are allotted to plots at random, and the randomisation is done afresh (independently) for every block.
2. Splitting plots is a feature of split-plot design.

Short trick: RBD: all treatments in every block, randomised afresh in each.

Concept: The term and concept of 'standard deviation' were introduced by Karl Pearson in 1893/94.

1. W.S. Gosset ('Student') gave the t-test; R.A. Fisher gave ANOVA and experimental designs; Galton gave regression and correlation concepts.

Short trick: Pearson → SD (1893) and correlation coefficient r.

Concept: Split-plot design is used for factorial experiments where one factor needs large plots and the factors are to be estimated with different precision.

1. Main-plot factor (irrigation, sowing date, tillage) is applied to large main plots – estimated with less precision.
2. Sub-plot factor (varieties, fertiliser doses) is applied to sub-plots – estimated with more precision, as is the interaction.

Short trick: Big-plot factor + unequal precision → split plot.

Concept: In a Latin square design the number of replications = number of treatments (t × t plots).

1. With fewer than 5 treatments, error degrees of freedom [(t–1)(t–2)] are too few (e.g. t = 4 gives only 6).
2. With more than 12 treatments, the square becomes too large (144+ plots) and heterogeneous.
3. So LSD is suitable only for about 5–12 treatments; CRD and RBD have no such restriction.

Short trick: LSD: 5 to 12 treatments.

Concept: Absolute measures (range, QD, MD, SD) carry the units of the data; relative measures are unit-free ratios.

1. Coefficient of variation CV = (SD / mean) × 100 – a relative measure used to compare variability of different series.
2. Quartile, mean and standard deviation are absolute measures.

Short trick: Coefficient = ratio = relative.