La plaga afecta la albahaca.

Not exactly. In a sentence about plants, plaga usually means a pest, infestation, or plant pest problem. It can sometimes be translated as plague, but in everyday gardening or farming Spanish, plaga often refers to insects, fungi, or other things damaging crops.

So here, La plaga afecta la albahaca most naturally suggests that a pest or infestation is harming the basil.

Afecta is the third-person singular present indicative form of afectar.

That means it goes with singular subjects like:

• la plaga afecta = the pest affects
• el humo afecta = the smoke affects

In English, it can mean affects, is affecting, or harms, depending on context.

Because both plaga and albahaca are feminine singular nouns:

• la plaga
• la albahaca

Spanish uses articles more often than English does. So even if English might sometimes say just basil, Spanish commonly says la albahaca.

Yes. The standard noun is la albahaca.

So you would say:

• la albahaca fresca
• la albahaca está creciendo

Even though it starts with a, it still uses la, not el, because the stressed syllable is not the first a sound.

Because afectar normally takes a direct object without a preposition.

So:

• La plaga afecta la albahaca = correct

Spanish uses the personal a mainly before specific people (and sometimes pets or personified animals), not before things or plants.

Compare:

• La plaga afecta la albahaca = the pest affects the basil
• La noticia afecta a María = the news affects María

It can be either one, depending on context.

Spanish often uses the definite article to talk about a thing in general:

• La albahaca necesita sol = basil needs sun

But it can also refer to a specific basil plant or basil crop already known in the conversation:

• La plaga afecta la albahaca del jardín = the pest affects the basil in the garden

Without more context, the sentence could be understood either way.

No. It is the normal Spanish order:

subject + verb + direct object

• La plaga = subject
• afecta = verb
• la albahaca = direct object

This is a very straightforward sentence pattern and matches basic English order pretty well.

A few helpful points:

• The h is silent in Spanish.
• The c before a sounds like k.
• The stress falls on the next-to-last syllable.

A rough approximation is ahl-ba-A-ka.

So the spelling has an h, but you do not pronounce an English h sound.

Yes, depending on context.

Afectar can be broader than English affect. In plant or health contexts, it often implies that something has a negative effect. So possible translations include:

• affects
• harms
• damages
• is affecting

For this sentence, The pest is harming the basil may sound more natural in English than a very literal The pest affects the basil.