NALP Landscape Industry Certified Interior Technician

A Dracaena marginata placed in an office with a light meter reading of 25 foot-candles is most likely to experience which condition over time?

• AEtiolation and loss of lower leaves due to insufficient light
• BLeaf scorch and bleaching from excessive light intensity
• CRapid vegetative growth with abundant side shoots
• DRoot rot caused by excess photosynthesis driving overwatering

Which unit of measurement describes the total daily light integral (DLI) received by an interior plant?

• AMoles of photons per square meter per day (mol/m²/day)
• BFoot-candles per hour
• CLux per square foot
• DWatts per square meter

Photosynthetically Active Radiation (PAR) is measured in which wavelength range?

• A400–700 nanometers
• B200–400 nanometers
• C700–1000 nanometers
• D300–500 nanometers

A Spathiphyllum wallisii (peace lily) begins showing brown leaf tips and margins. The growing medium is consistently moist and the plant is located 8 feet from a window. What is the most probable cause?

• ALow relative humidity causing transpiration to exceed water uptake at leaf margins
• BOverwatering leading to anaerobic root conditions
• CExcessive light causing photoinhibition at leaf tips
• DIron deficiency causing interveinal chlorosis

When using a moisture meter to assess a sub-irrigated planter, where should the probe be inserted for the most accurate reading?

• AIn the growing medium midway between the water reservoir and the surface
• BDirectly into the water reservoir
• CAt the very surface of the growing medium
• DThrough the drainage holes into the saucer

Which watering practice best describes the 'drench-and-dry' method used in top-watering interior plantscapes?

• AApplying water thoroughly until it drains from the pot, then allowing the medium to parti…
• BApplying a small amount of water daily to keep the medium constantly moist
• CSubmerging the container in water until bubbles stop, then draining completely
• DMisting the foliage daily while withholding water from the root zone

In a wicking sub-irrigation system, what growing medium characteristic is most critical for reliable capillary water movement to plant roots?

• AHigh porosity with fine particle sizes to maintain capillary continuity
• BLarge aggregate particles to maximize drainage rate
• CHigh organic content to retain maximum water at the surface
• DLow pH (4.5–5.0) to enhance cation exchange in the wicking zone

Which of the following correctly identifies Pothos (Epipremnum aureum) as an interiorscape plant?

• AA trailing vine in the family Araceae with heart-shaped leaves that may be all green or v…
• BA rosette-forming succulent with stiff, sword-shaped leaves and a central spike
• CAn upright tree-form plant with large, wavy, dark green leaves and white spathe flowers
• DA clumping grass-like plant with narrow, arching leaves striped green and white

Aglaonema (Chinese evergreen) is particularly valued in interiorscaping because it:

• ATolerates very low light levels (as low as 10–15 foot-candles) and irregular watering
• BRequires full sun (500+ foot-candles) and daily misting to thrive indoors
• CProduces abundant flowering year-round without supplemental fertilization
• DGrows best in a soil-free hydroponic NFT system at pH 7.5

A Ficus benjamina (weeping fig) in a lobby has recently dropped most of its leaves after being moved from a greenhouse to its installation site. What is the most likely explanation?

• AAcclimation stress from changes in light intensity and air circulation during relocation
• BRoot rot caused by over-irrigation during transport
• CBoron toxicity from tap water with high mineral content
• DInfestation by fungus gnats attacking the root system

Which Dracaena species is characterized by slender cane-like stems, narrow sword-shaped leaves with red or magenta margins, and tolerance for low light?

• ADracaena marginata
• BDracaena fragrans (corn plant)
• CDracaena sanderiana (lucky bamboo)
• DDracaena reflexa (pleomele)

An interiorscape technician notices that several Dracaena fragrans (corn plants) on a service route have developed fluoride-induced tip burn. Which corrective measure is most appropriate?

• ASwitch to fluoride-free water sources or leach the medium to remove accumulated fluoride…
• BApply a calcium nitrate foliar spray to neutralize foliar fluoride uptake
• CRepot immediately into fresh acidic growing medium (pH 4.5)
• DIncrease fertilizer applications to dilute fluoride concentration in the medium

Which of the following is a correct identification of Spathiphyllum wallisii (peace lily)?

• AClumping herbaceous plant with dark green, lance-shaped glossy leaves and white spathe fl…
• BErect succulent with thick, fleshy, mottled gray-green leaves in a rosette
• CTrailing vine with small, rounded green and silver-variegated leaves
• DTree-form plant with compound pinnate leaves and smooth gray bark

During routine pruning of a Ficus elastica (rubber plant), the technician notices milky white latex oozing from cut stems. What is the correct response?

• AWear gloves and avoid contact with the latex, which can cause skin irritation and is a se…
• BApply the latex as a natural rooting hormone on the cut ends
• CImmediately report a chemical spill and dispose of all plant material
• DUse the latex as a natural fungicide by spreading it on the growing medium surface

What is the primary purpose of 'grooming' (as distinct from pruning) during an interiorscape service call?

• ARemoving dead, yellowed, or damaged leaves and wiping foliage to maintain aesthetic appea…
• BReducing plant size by cutting back stems to the desired height
• CRemoving flowers to redirect energy to root development
• DRepotting plants into larger containers to stimulate growth

When pruning a Schefflera arboricola (dwarf umbrella tree) to reduce height by one-third, where should cuts be made?

• AJust above a node or lateral branch to encourage branching from that point
• BMidway between two nodes to produce a clean flush cut
• CAt the soil line to force basal regeneration from the roots
• DThrough the main trunk at the desired height regardless of node location

What distinguishes a sub-irrigation (self-watering) planter from a conventional container in terms of water delivery?

• ASub-irrigation delivers water from a reservoir below the root zone upward by capillary ac…
• BSub-irrigation applies water overhead using a drip emitter on a timed schedule
• CSub-irrigation uses a perforated pipe buried horizontally to flood the root zone periodic…
• DSub-irrigation recirculates water continuously through the growing medium using a pump

A hydroponic NFT (Nutrient Film Technique) system installed in an interior living wall requires the solution pH to be maintained at which range for most tropical foliage plants?

• A5.5–6.5
• B7.0–8.0
• C4.0–4.5
• D6.8–7.5

What is the most common water quality issue that causes white crusty deposits on the growing medium surface and container rims in interior plantscapes?

• ASoluble salt accumulation from hard water minerals and fertilizer residues
• BCalcium deficiency causing calcium oxalate precipitation on the medium
• CFungal mycelium growing on the dry medium surface
• DMagnesium carbonate deposited by the HVAC condensation system

On a service route, a technician finds a Sansevieria trifasciata (snake plant) with soft, mushy, brown stems at the base. What is the most likely diagnosis and corrective action?

• ARoot and crown rot from overwatering; remove affected tissue and reduce irrigation freque…
• BSunscald from excessive light; relocate to a shadier position and increase watering
• CPotassium deficiency; apply a potassium sulfate drench immediately
• DMite infestation causing cellular collapse; apply a registered miticide at base applicati…

During a service visit, a technician discovers an Aglaonema with pale yellow-green new growth but normal dark green older foliage. This pattern most likely indicates:

• AIron or manganese deficiency (interveinal chlorosis on young leaves from micronutrient de…
• BNitrogen deficiency causing uniform yellowing of old leaves first
• CPhosphorus toxicity causing necrosis on leaf tips of older leaves
• DVirus infection causing mosaic patterning on all leaves uniformly

What is the correct definition of 'foot-candle' as used in measuring interior plant light levels?

• AThe amount of illuminance produced by one candela source at a distance of one foot
• BThe number of photons per second reaching one square meter of surface
• CThe ratio of reflected light to incident light on a plant leaf surface
• DThe total energy in watts emitted by a light source in the PAR spectrum

Which of the following tropical foliage plants is in the family Araceae and produces showy inflorescences with a waxy spathe?

• AAnthurium andraeanum
• BDracaena deremensis
• CChamaedorea elegans (parlor palm)
• DCissus rhombifolia (grape ivy)

A client complains that a Chamaedorea elegans (parlor palm) in their office is losing lower fronds and producing new growth slowly. The light meter reads 40 foot-candles. What is the most appropriate recommendation?

• AThe light level is at the lower acceptable limit for Chamaedorea; recommend adding supple…
• BReplace the parlor palm with a full-sun palm species such as Washingtonia robusta
• CIncrease watering frequency to twice daily to compensate for the low light
• DApply a high-nitrogen granular fertilizer monthly to stimulate new frond growth

Which pruning technique is used to rejuvenate an overgrown Spathiphyllum by removing crowded stems at soil level to encourage new basal shoots?

• AThinning cuts made at the base of overcrowded stems to the growing point at soil level
• BHeading cuts made midway through each stem to reduce overall height by 50%
• CTip pinching of all stems to one inch above the soil
• DStub cuts leaving 6-inch stubs above the soil to protect growing points

A pesticide label states 'signal word: DANGER.' What does this indicate about the product?

• AThe product is highly toxic (Toxicity Category I) and may be fatal in small amounts if in…
• BThe product is moderately toxic (Toxicity Category II) and may cause harm only through pr…
• CThe product is a restricted-use pesticide that requires a commercial applicator license t…
• DThe product poses a flammability hazard and must be stored away from open flames

Which section of the pesticide label contains legally required information about what pests the product is registered to control and which plants it is registered for use on?

• ADirections for Use (including Pest and Site sections)
• BPrecautionary Statements
• CPhysical and Chemical Hazards
• DStorage and Disposal

A Material Safety Data Sheet (MSDS / SDS) is divided into 16 sections per GHS/OSHA HazCom 2012 requirements. Which section contains first aid measures?

• ASection 4
• BSection 1
• CSection 8
• DSection 11

Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), which statement correctly describes the legal requirement for pesticide use?

• APesticides must be used in accordance with label directions; using a pesticide inconsiste…
• BPesticide labels are guidelines only; professional applicators may deviate if they use be…
• CFIFRA requires pesticide registration only for outdoor use; indoor interiorscape applicat…
• DA certified applicator may use any registered pesticide on any site without site-specific…

What minimum personal protective equipment (PPE) is typically required when applying a pesticide spray labeled 'WARNING' (Category II) to interior plants?

• AChemical-resistant gloves, long sleeves, long pants, and protective eyewear as specified…
• BOnly safety glasses, since Category II products are safe without additional protection
• CA full-body Tyvek suit, supplied-air respirator, and face shield at all times
• DNo PPE is required for indoor applications since natural ventilation reduces exposure

Integrated Pest Management (IPM) for interior plantscapes prioritizes which sequence of pest control tactics?

• APrevention → cultural controls → biological controls → least-toxic chemical controls → co…
• BImmediate broad-spectrum pesticide application at the first sign of any pest
• CBiological controls only, with no pesticide applications permitted under any circumstances
• DChemical applications first, followed by biological controls if resistance develops

Which beneficial organism is most commonly used in interiorscape IPM programs to control fungus gnats (Bradysia spp.)?

• ASteinernema feltiae (entomopathogenic nematodes) applied as a soil drench targeting larvae
• BTrichogramma wasps released to parasitize fungus gnat pupae on the medium surface
• CPhytoseiulus persimilis predatory mites applied to the medium surface to consume larvae
• DBeauveria bassiana foliar sprays to control adult fungus gnats in flight

An interiorscape technician identifies a fine webbing on the undersides of Ficus leaves along with stippled, bronze discoloration. What pest is most likely responsible?

• ATwo-spotted spider mite (Tetranychus urticae)
• BFungus gnats (Bradysia spp.) whose adults fed on leaf undersides
• CMealybugs forming a protective wax covering on leaf undersides
• DScale insects producing sticky honeydew that becomes the webbing

Mealybugs on interior plants are most effectively identified by which characteristic?

• AWhite cottony or waxy filamentous masses in leaf axils, stem crevices, and on roots
• BHard brown hemispherical bumps firmly attached to stems and leaf midribs
• CFine white powder on upper leaf surfaces that can be wiped off
• DSmall black specks on leaf surfaces surrounded by a yellow halo

Which active ingredient in insecticidal soap is responsible for its efficacy against soft-bodied insects such as aphids and mealybugs?

• APotassium salts of fatty acids, which disrupt the insect's outer cuticle and cell membran…
• BPyrethrin, which disrupts the sodium channels in the insect nervous system
• CImidacloprid, which blocks nicotinic acetylcholine receptors in insect neurons
• DAzadirachtin, which disrupts molting hormones and inhibits feeding

Scale insects on interior Ficus plants are most difficult to control with contact pesticides because:

• AAdult scale insects are protected by a waxy or shell-like covering that prevents pesticid…
• BScale insects are immune to all contact pesticides due to natural resistance
• CScale insects only feed at night, making daytime pesticide applications ineffective
• DScale insects are protected inside leaf tissue and cannot be reached by surface applicati…

What is the function of a nitrogen fertilizer's N number in the guaranteed analysis (e.g., 20-10-10)?

• AIt represents the percentage of elemental nitrogen by weight in the fertilizer product
• BIt represents the number of nitrogen molecules per liter of solution
• CIt indicates the soil pH adjustment caused by the nitrogen fraction
• DIt represents the nitrogen release rate in days per application

For most interior foliage plants, which fertilizer application approach is most appropriate to avoid salt buildup in interior containers?

• AApply a dilute liquid fertilizer at one-quarter to one-half the recommended rate at every…
• BApply the maximum recommended rate of granular fertilizer once per year in spring
• CApply liquid fertilizer at full strength at every watering throughout the year
• DTop-dress with slow-release granular fertilizer monthly regardless of plant growth rate

Which macronutrient is primarily responsible for lush green color in foliage plants, and what symptom results from its deficiency?

• ANitrogen; deficiency causes uniform yellowing (chlorosis) beginning on older lower leaves…
• BPhosphorus; deficiency causes purple or red discoloration of older leaves
• CPotassium; deficiency causes interveinal chlorosis beginning on young leaves
• DCalcium; deficiency causes brown leaf tips on the newest growth

An interior plantscape technician measures the electrical conductivity (EC) of water draining from a container planting and gets a reading of 3.5 dS/m. This reading indicates:

• AExcessive soluble salt accumulation that should be corrected by leaching with fresh water
• BAn optimal salt level for actively growing tropical foliage plants
• CSeverely low fertility; the plant needs immediate high-nitrogen fertilizer
• DNormal tap water quality with no concerns for plant health

Which nutrient deficiency is most common in interior plants watered with highly alkaline water (pH above 8.0)?

• AIron (Fe) deficiency, because high pH causes iron to precipitate as iron hydroxide, reduc…
• BNitrogen (N) deficiency, because alkaline conditions inhibit nitrate absorption through r…
• CMagnesium (Mg) deficiency, because high pH increases magnesium solubility and leaching
• DSulfur (S) deficiency, because alkaline water neutralizes sulfate ions in the growing med…

When providing service to an interior plantscape at a healthcare facility, what additional IPM consideration is most important compared to a typical office setting?

• AUse only pesticides registered and approved for use in occupied sensitive environments; f…
• BApply pesticides at twice the label rate to ensure rapid control in high-risk settings
• CForego all pest control to avoid any pesticide exposure in healthcare settings
• DIncrease fertilizer applications to strengthen plant immunity against pests in high-traff…

What type of nitrogen source in a fertilizer releases nutrients slowly by microbiological breakdown and is safest for use in interior containerized plants?

• AWater-insoluble nitrogen (WIN) from sources such as urea-formaldehyde or methylene urea
• BPotassium nitrate (KNO₃), which is fully water-soluble and immediately available
• CAmmonium sulfate, which acidifies the growing medium and releases rapidly
• DMonoammonium phosphate (MAP), which releases nitrogen instantaneously upon dissolving

A technician observes uniform yellowing of leaves across all age groups on a Hedera helix (English ivy) with no pest symptoms. The soil pH tests at 7.8 and the plant was recently fertilized. What is the most likely cause?

• AMultiple nutrient deficiencies caused by high pH locking out iron, manganese, and other m…
• BNitrogen toxicity from over-fertilization causing chlorophyll breakdown
• CRoot rot from overwatering eliminating all nitrogen uptake
• DNatural seasonal senescence in Hedera helix during winter months

During a service call, a client asks why fungus gnats keep appearing around their potted Pothos. What is the most accurate and actionable explanation?

• AFungus gnat adults lay eggs in consistently moist growing medium surfaces; allowing the t…
• BFungus gnats are attracted to the Pothos fragrance; replacing with an unscented plant spe…
• CFungus gnat larvae emerge from the growing medium because of fluoride toxicity; replacing…
• DFungus gnats are a symptom of spider mite infestation; controlling mites will eliminate t…

Which pesticide active ingredient is derived from the neem tree (Azadirachta indica) and acts as an insect growth regulator affecting molting?

• AAzadirachtin
• BSpinosad
• CPyrethrin
• DImidacloprid

What is the primary nutritional role of potassium (K) in interior foliage plants?

• ARegulation of stomatal opening, enzyme activation, and osmoregulation (water balance) in…
• BPrimary component of chlorophyll that drives photosynthesis in low-light conditions
• CStructural component of cell walls that prevents wilting in tropical species
• DFormation of proteins and nucleic acids essential for vegetative growth